diff --git a/CHANGES b/CHANGES
index 8f32ad6..0accdf4 100644
--- a/CHANGES
+++ b/CHANGES
@@ -54,6 +54,9 @@ corrections:
 	Thanks to Lorenzo Monti for pointing me to this issue
 
 porting:
+	Red Hat issue 1020203: configure checks fail with some compilers.
+	Use case: clang
+
 	Performed changes for Fedora release 19
 
 	Adapted, improved test.sh script
diff --git a/config.h.in b/config.h.in
index 0f805d4..ccf6ec9 100644
--- a/config.h.in
+++ b/config.h.in
@@ -63,13 +63,13 @@
 #undef HAVE_SOCKET
 
 /* Define if you have the strdup function.  */
-#undef HAVE_STRDUP
+#undef HAVE_PROTOTYPE_LIB_strdup
 
 /* Define if you have the strerror function.  */
-#undef HAVE_STRERROR
+#undef HAVE_PROTOTYPE_LIB_strerror
 
 /* Define if you have the strstr function.  */
-#undef HAVE_STRSTR
+#undef HAVE_PROTOTYPE_LIB_strstr
 
 /* Define if you have the strtod function.  */
 #undef HAVE_STRTOD
@@ -96,7 +96,7 @@
 #undef HAVE_GETADDRINFO
 
 /* Define if you have the getipnodebyname function.  */
-#undef HAVE_GETIPNODEBYNAME
+#undef HAVE_PROTOTYPE_LIB_getipnodebyname
 
 /* Define if you have the setgroups function. */
 #undef HAVE_SETGROUPS
@@ -105,10 +105,10 @@
 #undef HAVE_INET_ATON
 
 /* Define if you have the memrchr function. */
-#undef HAVE_MEMRCHR
+#undef HAVE_PROTOTYPE_LIB_memrchr
 
 /* Define if you have the if_indextoname function. */
-#undef HAVE_IF_INDEXTONAME
+#undef HAVE_PROTOTYPE_LIB_if_indextoname
 
 /* Define if you have the sigaction function */
 #undef HAVE_SIGACTION
@@ -376,6 +376,9 @@
 /* define if your struct in_pktinfo has component ipi_spec_dst */
 #undef HAVE_PKTINFO_IPI_SPEC_DST
 
+/* define if you have struct in6_pktinfo */
+#undef HAVE_STRUCT_IN6_PKTINFO
+
 /* define if your struct ip has ip_hl; otherwise assume ip_vhl */
 #undef HAVE_STRUCT_IP_IP_HL
 
@@ -404,7 +407,7 @@
 #undef HAVE_UNLOCKPT
 
 /* Define if you have the ptsname function */
-#undef HAVE_PTSNAME
+#undef HAVE_PROTOTYPE_LIB_ptsname
 
 /* Define if you have the /dev/ptmx pseudo terminal multiplexer */
 #undef HAVE_DEV_PTMX
diff --git a/configure.in b/configure.in
index 942b45b..3f4d427 100644
--- a/configure.in
+++ b/configure.in
@@ -1,4 +1,4 @@
-nl source: configure.in
+dnl source: configure.in
 dnl Copyright Gerhard Rieger
 dnl Published under the GNU General Public License V.2, see file COPYING
 
@@ -41,12 +41,16 @@ AC_CHECK_PROG(AR, ar, ar, gar)
 # fail
 AC_LANG_COMPILER_REQUIRE()
 
-if test "$GCC" = yes; then
+if test "$CC" = "gcc"; then
    CFLAGS="$CFLAGS -D_GNU_SOURCE -Wall -Wno-parentheses"
    ERRONWARN="-Werror -O0"
+elif test "$CC" = "clang"; then
+   CFLAGS="$CFLAGS -D_GNU_SOURCE -Wall -Wno-parentheses"
+   ERRONWARN="-Werror -O0"
+#elif Sun Studio
+#   ERRONWARN="-errwarn"
 else
-   # Sun Studio?
-   ERRONWARN="-errwarn"
+   ERRONWARN=
 fi
 export CFLAGS
 
@@ -95,6 +99,25 @@ AC_CHECK_FUNC(gethostent, , AC_CHECK_LIB(nsl, gethostent))
 AC_CHECK_FUNC(setsockopt, , AC_CHECK_LIB(socket, setsockopt))
 
 
+dnl Check for function prototype and in lib
+dnl arg1: function name
+dnl arg2: required include files beyond sysincludes.h
+define(AC_CHECK_PROTOTYPE_LIB,[
+AC_MSG_CHECKING(for $1 prototype)
+AC_CACHE_VAL(sc_cv_have_prototype_lib_$1,
+[CFLAGS1="$CFLAGS"; CFLAGS="$ERRONWARN -Wall $CFLAGS1";
+ AC_TRY_LINK([#include "sysincludes.h"
+$2],[return(&$1==(void *)&$1);],
+ [sc_cv_have_prototype_lib_$1=yes],
+ [sc_cv_have_prototype_lib_$1=no]);
+ CFLAGS="$CFLAGS1"])
+if test $sc_cv_have_prototype_lib_$1 = yes; then
+   AC_DEFINE(HAVE_PROTOTYPE_LIB_$1)
+fi
+AC_MSG_RESULT($sc_cv_have_prototype_lib_$1)
+])
+
+
 dnl Check for hstrerror prototype
 AC_MSG_CHECKING(for hstrerror prototype)
 AC_CACHE_VAL(sc_cv_have_prototype_hstrerror,
@@ -560,7 +583,7 @@ if test -n "$WITH_FIPS"; then
 fi
 
 if test -n "$WITH_FIPS"; then
-  AC_MSG_NOTICE(checking for components of OpenSSL FIPS)
+  AC_MSG_CHECKING(for components of OpenSSL FIPS)
   # first, we need to find the include file <openssl/fips.h>
   AC_CACHE_VAL(sc_cv_have_openssl_fips_h,
     [AC_TRY_COMPILE([#define OPENSSL_FIPS
@@ -707,12 +730,26 @@ AC_PROG_GCC_TRADITIONAL
 AC_FUNC_MEMCMP
 AC_TYPE_SIGNAL
 AC_FUNC_STRFTIME
-AC_CHECK_FUNCS(putenv select poll socket strdup strerror strstr strtod strtol)
+AC_CHECK_FUNCS(putenv select poll socket strtod strtol)
 AC_CHECK_FUNCS(strtoul uname getpgid getsid getaddrinfo)
-AC_CHECK_FUNCS(getipnodebyname setgroups inet_aton memrchr)
-AC_CHECK_FUNCS(if_indextoname)
+AC_CHECK_FUNCS(setgroups inet_aton)
+AC_CHECK_FUNCS()
 
-AC_CHECK_FUNCS(grantpt unlockpt ptsname)
+AC_CHECK_FUNCS(grantpt unlockpt)
+
+# GR AC_CHECK_FUNCS only checks linking, not prototype. This may lead to implicit
+# function declarations and to SIGSEGV on systems with 32bit int and 64bit pointer
+
+###################################
+# check for prototype and existence of functions that return a pointer
+# defines in config.h: HAVE_PROTOTYPE_LIB_$1
+AC_CHECK_PROTOTYPE_LIB(strdup)
+AC_CHECK_PROTOTYPE_LIB(strerror)
+AC_CHECK_PROTOTYPE_LIB(strstr)
+AC_CHECK_PROTOTYPE_LIB(getipnodebyname)
+AC_CHECK_PROTOTYPE_LIB(memrchr)
+AC_CHECK_PROTOTYPE_LIB(if_indextoname)
+AC_CHECK_PROTOTYPE_LIB(ptsname)
 
 
 AC_MSG_CHECKING(for long long)
@@ -905,10 +942,11 @@ AC_CACHE_VAL(ac_cv_ispeed_offset,
  [conftestspeedoff="conftestspeedoff.out"
  AC_TRY_RUN([
   #include <errno.h>
+  #include <stdlib.h>
   #include <stdio.h>
   #include <termios.h>
   #include <string.h>
-  main(){
+  int main(){
     struct termios t;
     FILE *f;
     if ((f=fopen("$conftestspeedoff","w"))==NULL){
@@ -1202,6 +1240,18 @@ if test $sc_cv_struct_in_pktinfo = 'yes'; then
    AC_MSG_RESULT($sc_cv_pktinfo_ipi_spec_dst)
 fi
 
+dnl check for struct in6_pktinfo
+AC_MSG_CHECKING(for struct in6_pktinfo)
+AC_CACHE_VAL(sc_cv_struct_in6_pktinfo,
+[AC_TRY_COMPILE([#include "sysincludes.h"],
+[struct in6_pktinfo s;],
+[sc_cv_struct_in6_pktinfo=yes],
+[sc_cv_struct_in6_pktinfo=no])])
+if test $sc_cv_struct_in6_pktinfo = yes; then
+   AC_DEFINE(HAVE_STRUCT_IN6_PKTINFO)
+fi
+AC_MSG_RESULT($sc_cv_struct_in6_pktinfo)
+
 dnl check for ip_hl in struct ip
 AC_MSG_CHECKING(for struct ip.ip_hl)
 AC_CACHE_VAL(sc_cv_struct_ip_ip_hl,
@@ -1304,7 +1354,9 @@ AC_MSG_RESULT($ac_cv_have_c99_snprintf)
 
 AC_MSG_CHECKING(if printf has Z modifier)
 AC_CACHE_VAL(ac_cv_have_z_modifier,
+if test "$cc" = gcc; then
 [AC_TRY_RUN([
+#include <stdlib.h>
 #include <stdio.h>
 int main(void){
 char s[16];
@@ -1313,7 +1365,10 @@ exit(strcmp(s,"1"));
 }],
 [ac_cv_have_z_modifier=yes],
 [ac_cv_have_z_modifier=no],
-[ac_cv_have_z_modifier=no])])
+[ac_cv_have_z_modifier=no])]
+else ac_cv_have_z_modifier=no
+fi
+)
 if test $ac_cv_have_z_modifier = yes; then
    AC_DEFINE(HAVE_FORMAT_Z)
 fi
@@ -1329,10 +1384,11 @@ AC_CACHE_CHECK(shift offset of $1, $2,
  conftestoffset="conftestoffset.out"
  AC_TRY_RUN([
  #include <errno.h>
+ #include <stdlib.h>
  #include <stdio.h>
  #include <termios.h>
  #include <string.h>
- main(){
+ int main(){
     unsigned int i,n=$1;
     FILE *f;
     if ((f=fopen("$conftestoffset","w"))==NULL){
@@ -1365,6 +1421,116 @@ AC_SHIFT_OFFSET(TABDLY, sc_cv_sys_tabdly_shift)
 AC_SHIFT_OFFSET(CSIZE,  sc_cv_sys_csize_shift)
 
 
+dnl Find what physical type (basic C type) is equivalent to the given type.
+dnl If possible we try to compile simple test code and get no warning only with
+dnl the matching type.
+dnl If this method does not seem to work we run test programs that print the
+dnl length and signedness of the type.
+
+dnl do we have a -Werror option? 
+dnl Does the test code compile with -Werror when types fit?
+CHANCE_TO_TYPECHECK=1
+CFLAGS1="$CFLAGS"; CFLAGS="$ERRONWARN $(echo "$CFLAGS1" | sed -e 's@-Wall@@g')"
+AC_TRY_COMPILE([#include <stdlib.h>],[int u; int v; exit(&u==&v);],,CHANCE_TO_TYPECHECK=0)
+CFLAGS="$CFLAGS1"
+
+dnl Does the test code compile without -Werror when types do not fit?
+if test "$CHANCE_TO_TYPECHECK" -ne 0; then
+ AC_TRY_COMPILE([#include <stdlib.h>],[int u; unsigned int v; exit(&u==&v);],,CHANCE_TO_TYPECHECK=0)
+fi
+
+dnl Does the test code fail to compile with -Werror when types do not fit?
+if test "$CHANCE_TO_TYPECHECK" -ne 0; then
+ CFLAGS1="$CFLAGS"; CFLAGS="$ERRONWARN $(echo "$CFLAGS1" | sed -e 's@-Wall@@g')"
+ AC_TRY_COMPILE([#include <stdlib.h>],[int u; unsigned int v; exit(&u==&v);],CHANCE_TO_TYPECHECK=0,)
+ CFLAGS="$CFLAGS1"
+fi
+
+if test "$CHANCE_TO_TYPECHECK" -ne 0; then
+   AC_MSG_NOTICE(using compile -Werror method to find basic types)
+else
+   AC_MSG_NOTICE(using code run method to find basic types)
+fi
+
+
+dnl see AC_BASIC_TYPE
+define(AC_BASIC_TYPE_GCC,[
+AC_CACHE_CHECK(for equivalent simple type of $2, $4,
+[CFLAGS1="$CFLAGS"; CFLAGS="$ERRONWARN $(echo "$CFLAGS1" | sed -e 's@-Wall@@g')"
+ dnl echo "echo: trying short for $2" >&2
+ AC_TRY_COMPILE([$1],[$2 u; short v; return(&u==&v);],
+ [$4="1 /* short */"],
+ [AC_TRY_COMPILE([$1],[$2 u; unsigned short v; return(&u==&v);],
+  [$4="2 /* unsigned short */"],
+  [AC_TRY_COMPILE([$1],[$2 u; int v; return(&u==&v);],
+   [$4="3 /* int */"],
+   [AC_TRY_COMPILE([$1],[$2 u; unsigned int v; return(&u==&v);],
+    [$4="4 /* unsigned int */"],
+    [AC_TRY_COMPILE([$1],[$2 u; long v; return(&u==&v);],
+     [$4="5 /* long */"],
+     [AC_TRY_COMPILE([$1],[$2 u; unsigned long v; return(&u==&v);],
+      [$4="6 /* unsigned long */"],
+      [AC_TRY_COMPILE([$1],[$2 u; long long v; return(&u==&v);],
+       [$4="7 /* long long */"],
+       [AC_TRY_COMPILE([$1],[$2 u; unsigned long long v; return(&u==&v);],
+        [$4="8 /* unsigned long long */"],
+        [$4="0 /* unknown, taking default */"
+]) ]) ]) ]) ]) ]) ]) ])
+ CFLAGS="$CFLAGS1" ])
+AC_DEFINE_UNQUOTED($3, ${$4})
+])
+
+dnl see AC_BASIC_TYPE
+define(AC_BASIC_TYPE_OTHER,[
+AC_CACHE_CHECK(for equivalent simple type of $2, $4,
+[AC_TRY_RUN([
+$1
+int main() { return!(sizeof($2)==sizeof(short));}],
+ # same length as short
+ AC_TRY_RUN([
+$1
+int main() { $2 x=-1; return !(x<0);}],
+  [$4="1 /* short */"],
+  [$4="2 /* unsigned short */"]),
+ # length differs from short, try others
+ AC_TRY_RUN([
+$1
+int main() { return!(sizeof($2)==sizeof(int));}],
+  # same length as int
+  AC_TRY_RUN([
+$1
+int main() { $2 x=-1; return !(x<0);}],
+   [$4="3 /* int */"],
+   [$4="4 /* unsigned int */"]),
+  # length differs from int, try others
+  AC_TRY_RUN([
+$1
+int main() { return !(sizeof($2)==sizeof(long));}],
+   # same length as long
+   AC_TRY_RUN([
+$1
+int main() { $2 x=-1; return !(x<0);}],
+    [$4="5 /* long */"],
+    [$4="6 /* unsigned long */"] ),
+   # length differs from long, try others
+   AC_TRY_RUN([
+$1
+int main() { return !(sizeof($2)==sizeof(long long));}],
+   # same length as long long
+     AC_TRY_RUN([
+$1
+int main() { $2 x=-1; return !(x<0);}],
+     [$4="7 /* long long */"],
+     [$4="8 /* unsigned long long */"] ),
+     [$4="0 /* unknown */"]
+   )
+  )
+ )
+)
+])
+AC_DEFINE_UNQUOTED($3, ${$4})
+])
+
 dnl find what physical type (basic C type) is equivalent to the given type.
 dnl arg1: include file(s)
 dnl arg2: type name
@@ -1373,28 +1539,91 @@ dnl arg4: cache variable (might be constructed automatically)
 dnl   output values: 1..short, 2..unsigned short, 3..int, 4..u-int,
 dnl                  5..long, 6..u-long; others not yet supported
 define(AC_BASIC_TYPE,[
-AC_CACHE_CHECK(for equivalent simple type of $2, $4,
+   if test "$CHANCE_TO_TYPECHECK" -ne 0; then
+      AC_BASIC_TYPE_GCC([$1],[$2],[$3],[$4])
+   else
+      AC_BASIC_TYPE_OTHER([$1],[$2],[$3],[$4])
+   fi
+])
+
+
+dnl See AC_TYPEOF_COMPONENT
+dnl This version is for compilers with -Werror or so: gcc, clang, Sun Studio?
+define(AC_TYPEOF_COMPONENT_GCC,[
+AC_CACHE_CHECK(for basic type of $2.$3, $5,
 [CFLAGS1="$CFLAGS"; CFLAGS="$ERRONWARN $(echo "$CFLAGS1" | sed -e 's@-Wall@@g')"
- AC_TRY_COMPILE([$1],[$2 u; short v; &u==&v;],
- [$4="1 /* short */"],
- [AC_TRY_COMPILE([$1],[$2 u; unsigned short v; &u==&v;],
-  [$4="2 /* unsigned short */"],
-  [AC_TRY_COMPILE([$1],[$2 u; int v; &u==&v;],
-   [$4="3 /* int */"],
-   [AC_TRY_COMPILE([$1],[$2 u; unsigned int v; &u==&v;],
-    [$4="4 /* unsigned int */"],
-    [AC_TRY_COMPILE([$1],[$2 u; long v; &u==&v;],
-     [$4="5 /* long */"],
-     [AC_TRY_COMPILE([$1],[$2 u; unsigned long v; &u==&v;],
-      [$4="6 /* unsigned long */"],
-      [AC_TRY_COMPILE([$1],[$2 u; long long v; &u==&v;],
-       [$4="7 /* long long */"],
-       [AC_TRY_COMPILE([$1],[$2 u; unsigned long long v; &u==&v;],
-        [$4="8 /* unsigned long long */"],
-        [$4="0 /* unknown, taking default */"
+AC_TRY_COMPILE([$1],[$2 u;short v; return(&u.$3==&v);],
+[$5="1 /* short */"],
+[AC_TRY_COMPILE([$1],[$2 u; unsigned short v; return(&u.$3==&v);],
+ [$5="2 /* unsigned short */"],
+ [AC_TRY_COMPILE([$1],[$2 u; int v; return(&u.$3==&v);],
+  [$5="3 /* int */"],
+  [AC_TRY_COMPILE([$1],[$2 u; unsigned int v; return(&u.$3==&v);],
+   [$5="4 /* unsigned int */"],
+   [AC_TRY_COMPILE([$1],[$2 u; long v; return(&u.$3==&v);],
+    [$5="5 /* long */"],
+    [AC_TRY_COMPILE([$1],[$2 u; unsigned long v; return(&u.$3==&v);],
+     [$5="6 /* unsigned long */"],
+     [AC_TRY_COMPILE([$1],[$2 u; long long v; return(&u.$3==&v);],
+      [$5="7 /* long long */"],
+      [AC_TRY_COMPILE([$1],[$2 u; unsigned long long v; return(&u.$3==&v);],
+       [$5="8 /* unsigned long long */"],
+       [$5="0 /* unknown, taking default */"
 ]) ]) ]) ]) ]) ]) ]) ])
  CFLAGS="$CFLAGS1" ])
-AC_DEFINE_UNQUOTED($3, ${$4})
+AC_DEFINE_UNQUOTED($4, ${$5})
+])
+
+dnl See AC_TYPEOF_COMPONENT
+dnl This version is for compilers with no -Werror or so
+define(AC_TYPEOF_COMPONENT_OTHER,[
+AC_CACHE_CHECK(for basic type of $2.$3, $5,
+[AC_TRY_RUN([
+$1
+int main() { $2 x; return!(sizeof(x.$3)==sizeof(short));}],
+ # same length as short
+ AC_TRY_RUN([
+$1
+int main() { $2 x; x.$3=-1; return !(x.$3<0);}],
+  [$5="1 /* short */"],
+  [$5="2 /* unsigned short */"]),
+ # length differs from short, try others
+ AC_TRY_RUN([
+$1
+int main() { $2 x; return!(sizeof(x.$3)==sizeof(int));}],
+  # same length as int
+  AC_TRY_RUN([
+$1
+int main() { $2 x; x.$3=-1; return !(x.$3<0);}],
+   [$5="3 /* int */"],
+   [$5="4 /* unsigned int */"]),
+  # length differs from int, try others
+  AC_TRY_RUN([
+$1
+int main() { $2 x; return !(sizeof(x.$3)==sizeof(long));}],
+   # same length as long
+   AC_TRY_RUN([
+$1
+int main() { $2 x; x.$3=-1; return !(x.$3<0);}],
+    [$5="5 /* long */"],
+    [$5="6 /* unsigned long */"] ),
+   # length differs from long, try others
+   AC_TRY_RUN([
+$1
+int main() { $2 x; return !(sizeof(x.$3)==sizeof(long long));}],
+   # same length as long long
+     AC_TRY_RUN([
+$1
+int main() { x $2; x.$3=-1; return !(x.$3<0);}],
+     [$5="7 /* long long */"],
+     [$5="8 /* unsigned long long */"] ),
+     [$5="0 /* unknown */"]
+   )
+  )
+ )
+)
+])
+AC_DEFINE_UNQUOTED($4, ${$5})
 ])
 
 dnl find what physical type (basic C type) describes the given struct or union
@@ -1405,28 +1634,11 @@ dnl arg3: variable or component (e.g., "st_ino")
 dnl arg4: output variable, values see AC_BASIC_TYPE
 dnl arg5: cache variable (might be constructed automatically)
 define(AC_TYPEOF_COMPONENT,[
-AC_CACHE_CHECK(for basic type of $2.$3, $5,
-[CFLAGS1="$CFLAGS"; CFLAGS="$ERRONWARN $(echo "$CFLAGS1" | sed -e 's@-Wall@@g')"
-AC_TRY_COMPILE([$1],[$2 u;short v; &u.$3==&v;],
-[$5="1 /* short */"],
-[AC_TRY_COMPILE([$1],[$2 u; unsigned short v; &u.$3==&v;],
- [$5="2 /* unsigned short */"],
- [AC_TRY_COMPILE([$1],[$2 u; int v; &u.$3==&v;],
-  [$5="3 /* int */"],
-  [AC_TRY_COMPILE([$1],[$2 u; unsigned int v; &u.$3==&v;],
-   [$5="4 /* unsigned int */"],
-   [AC_TRY_COMPILE([$1],[$2 u; long v; &u.$3==&v;],
-    [$5="5 /* long */"],
-    [AC_TRY_COMPILE([$1],[$2 u; unsigned long v; &u.$3==&v;],
-     [$5="6 /* unsigned long */"],
-     [AC_TRY_COMPILE([$1],[$2 u; long long v; &u.$3==&v;],
-      [$5="7 /* long long */"],
-      [AC_TRY_COMPILE([$1],[$2 u; unsigned long long v; &u.$3==&v;],
-       [$5="8 /* unsigned long long */"],
-       [$5="0 /* unknown, taking default */"
-]) ]) ]) ]) ]) ]) ]) ])
- CFLAGS="$CFLAGS1" ])
-AC_DEFINE_UNQUOTED($4, ${$5})
+   if test "$CHANCE_TO_TYPECHECK" -ne 0; then
+      AC_TYPEOF_COMPONENT_GCC([$1],[$2],[$3],[$4],[$5])
+   else
+      AC_TYPEOF_COMPONENT_OTHER([$1],[$2],[$3],[$4],[$5])
+   fi
 ])
 
 AC_BASIC_TYPE([#include <stdlib.h>], size_t, HAVE_BASIC_SIZE_T, sc_cv_type_sizet_basic)
@@ -1528,7 +1740,7 @@ AC_ARG_ENABLE(libwrap, [  --disable-libwrap       disable libwrap support],
 #
 # check if we find the components of libwrap ("tcpd" "tcpwrappers")
 if test -n "$WITH_LIBWRAP"; then
-  AC_MSG_NOTICE(checking for components of libwrap)
+  AC_MSG_CHECKING(for components of libwrap)
   # first, we need to find the include file <tcpd.h>
   AC_CACHE_VAL(sc_cv_have_tcpd_h,
     [AC_TRY_COMPILE([#include <sys/types.h>
@@ -1596,7 +1808,7 @@ fi
 
 # check of hosts_allow_table
 if test -n "$WITH_LIBWRAP"; then
-  AC_MSG_CHECKING(checking for hosts_allow_table)
+  AC_MSG_CHECKING(for hosts_allow_table)
   AC_CACHE_VAL(sc_cv_have_hosts_allow_table,
     [AC_TRY_COMPILE([#include <sys/types.h>
 #include <tcpd.h>],[hosts_allow_table="";],
diff --git a/filan.c b/filan.c
index e14e90d..b64ee5c 100644
--- a/filan.c
+++ b/filan.c
@@ -1,5 +1,5 @@
 /* source: filan.c */
-/* Copyright Gerhard Rieger 2001-2011 */
+/* Copyright Gerhard Rieger */
 /* Published under the GNU General Public License V.2, see file COPYING */
 
 /* the subroutine filan makes a "FILe descriptor ANalysis". It checks the
@@ -264,7 +264,7 @@ int filan_stat(
    if (filan_rawoutput) {
       snprintf(stdevstr, 8, F_dev, buf->st_dev);
    } else {
-      snprintf(stdevstr, 8, "%hu,%hu", (unsigned short)buf->st_dev>>8, (unsigned short)buf->st_dev&0xff);
+      snprintf(stdevstr, 8, "%hu,%hu", (unsigned short)(buf->st_dev>>8), (unsigned short)(buf->st_dev&0xff));
    }
    fprintf(outfile, "%4d: %s\t%s\t"
 #if HAVE_STAT64
@@ -299,7 +299,7 @@ int filan_stat(
 	   buf->st_mode, buf->st_nlink, buf->st_uid,
 	   buf->st_gid,
 #if HAVE_ST_RDEV
-	   (unsigned short)buf->st_rdev>>8, (unsigned short)buf->st_rdev&0xff,
+	   (unsigned short)(buf->st_rdev>>8), (unsigned short)(buf->st_rdev&0xff),
 #endif
 	   buf->st_size
 #if HAVE_ST_BLKSIZE
diff --git a/sycls.c b/sycls.c
index 3ba0b39..0f957fc 100644
--- a/sycls.c
+++ b/sycls.c
@@ -1239,7 +1239,7 @@ int Getaddrinfo(const char *node, const char *service,
 }
 #endif /* (_WITH_IP4 || _WITH_IP6) && HAVE_GETADDRINFO */
 
-#if (WITH_IP4 || WITH_IP6) && HAVE_GETIPNODEBYNAME
+#if (WITH_IP4 || WITH_IP6) && HAVE_PROTOTYPE_LIB_getipnodebyname
 struct hostent *Getipnodebyname(const char *name, int af, int flags,
                                 int *error_num) {
    struct hostent *result;
@@ -1254,7 +1254,7 @@ struct hostent *Getipnodebyname(const char *name, int af, int flags,
    }
    return result;
 }
-#endif /* (WITH_IP4 || WITH_IP6) && HAVE_GETIPNODEBYNAME */
+#endif /* (WITH_IP4 || WITH_IP6) && HAVE_PROTOTYPE_LIB_getipnodebyname */
 
 void *Malloc(size_t size) {
    void *result;
@@ -1396,7 +1396,7 @@ int Unlockpt(int fd) {
 }
 #endif /* HAVE_UNLOCKPT */
 
-#if HAVE_PTSNAME	/* AIX, not Linux */
+#if HAVE_PROTOTYPE_LIB_ptsname	/* AIX, not Linux */
 char *Ptsname(int fd) {
    char *result;
    int _errno;
@@ -1410,7 +1410,7 @@ char *Ptsname(int fd) {
    errno = _errno;
    return result;
 }
-#endif /* HAVE_PTSNAME */
+#endif /* HAVE_PROTOTYPE_LIB_ptsname */
 
 int Uname(struct utsname *buf) {
    int result, _errno;
diff --git a/sysincludes.h b/sysincludes.h
index 62ff117..07be96d 100644
--- a/sysincludes.h
+++ b/sysincludes.h
@@ -87,7 +87,7 @@
 #if HAVE_SYS_FILE_H
 #include <sys/file.h>	/* LOCK_EX, on AIX directly included */
 #endif
-#if _WITH_SOCKET
+#if WITH_IP4 || WITH_IP6
 #  if HAVE_NETINET_IN_H
 #include <netinet/in.h>	/* struct sockaddr_in, htonl() */
 #  endif
diff --git a/test.sh b/test.sh
index 0a1754b..ec63446 100755
--- a/test.sh
+++ b/test.sh
@@ -11718,7 +11718,7 @@ esac
 N=$((N+1))
 
 
-echo "summary: $((N-1)) tests, $((numOK+numFAILD+numCANT)) chosen; $numOK ok, $numFAIL failed, $numCANT could not be performed"
+echo "summary: $((N-1)) tests, $((numOK+numFAILD+numCANT)) selected; $numOK ok, $numFAIL failed, $numCANT could not be performed"
 
 if [ "$numFAIL" -gt 0 ]; then
     echo "FAILED: $listFAIL"
diff --git a/utils.c b/utils.c
index 2b13862..9807915 100644
--- a/utils.c
+++ b/utils.c
@@ -14,7 +14,7 @@
 #include "utils.h"
 
 
-#if !HAVE_MEMRCHR
+#if !HAVE_PROTOTYPE_LIB_memrchr
 /* GNU extension, available since glibc 2.1.91 */
 void *memrchr(const void *s, int c, size_t n) {
    const unsigned char *t = ((unsigned char *)s)+n;
@@ -25,7 +25,7 @@ void *memrchr(const void *s, int c, size_t n) {
       return NULL;
    return (void *)t;
 }
-#endif /* !HAVE_MEMRCHR */
+#endif /* !HAVE_PROTOTYPE_LIB_memrchr */
 
 void *memdup(const void *src, size_t n) {
    void *dest;
diff --git a/utils.h b/utils.h
index d2f2001..46ff9be 100644
--- a/utils.h
+++ b/utils.h
@@ -1,5 +1,5 @@
 /* source: utils.h */
-/* Copyright Gerhard Rieger 2001-2008 */
+/* Copyright Gerhard Rieger */
 /* Published under the GNU General Public License V.2, see file COPYING */
 
 #ifndef __utils_h_included
@@ -11,7 +11,7 @@ struct wordent {
    void *desc;
 } ;
 
-#if !HAVE_MEMRCHR
+#if !HAVE_PROTOTYPE_LIB_memrchr
 extern void *memrchr(const void *s, int c, size_t n);
 #endif
 extern void *memdup(const void *src, size_t n);
diff --git a/xio-ip.c b/xio-ip.c
index 8a74d4e..271c8d7 100644
--- a/xio-ip.c
+++ b/xio-ip.c
@@ -129,7 +129,7 @@ int xiogetaddrinfo(const char *node, const char *service,
 #if HAVE_GETADDRINFO
    struct addrinfo hints = {0};
    struct addrinfo *res = NULL;
-#else /* HAVE_GETIPNODEBYNAME || nothing */
+#else /* HAVE_PROTOTYPE_LIB_getipnodebyname || nothing */
    struct hostent *host;
 #endif
    int error_num;
@@ -314,7 +314,7 @@ int xiogetaddrinfo(const char *node, const char *service,
       }
    }
 
-#elif HAVE_GETIPNODEBYNAME /* !HAVE_GETADDRINFO */
+#elif HAVE_PROTOTYPE_LIB_getipnodebyname /* !HAVE_GETADDRINFO */
 
    if (node != NULL) {
       /* first fallback is getipnodebyname() */
@@ -362,7 +362,7 @@ int xiogetaddrinfo(const char *node, const char *service,
       freehostent(host);
    }
 
-#else /* !HAVE_GETIPNODEBYNAME */
+#else /* !HAVE_PROTOTYPE_LIB_getipnodebyname */
 
    if (node != NULL) {
       /* this is not a typical IP6 resolver function - but Linux
diff --git a/xio-ip6.c b/xio-ip6.c
index 23287a2..2e5c629 100644
--- a/xio-ip6.c
+++ b/xio-ip6.c
@@ -233,7 +233,7 @@ int xiolog_ancillary_ip6(struct cmsghdr *cmsg, int *num,
    msglen = cmsg->cmsg_len-((char *)CMSG_DATA(cmsg)-(char *)cmsg);
       envbuff[0] = '\0';
    switch (cmsg->cmsg_type) {
-#ifdef IPV6_PKTINFO
+#if defined(IPV6_PKTINFO) && HAVE_STRUCT_IN6_PKTINFO
    case IPV6_PKTINFO: {
       struct in6_pktinfo *pktinfo = (struct in6_pktinfo *)CMSG_DATA(cmsg);
       *num = 2;
@@ -245,7 +245,7 @@ int xiolog_ancillary_ip6(struct cmsghdr *cmsg, int *num,
 	       '\0', xiogetifname(pktinfo->ipi6_ifindex, scratch2, -1));
    }
       return STAT_OK;
-#endif /* defined(IPV6_PKTINFO) */
+#endif /* defined(IPV6_PKTINFO) && HAVE_STRUCT_IN6_PKTINFO */
 #ifdef IPV6_HOPLIMIT
    case IPV6_HOPLIMIT:
       typbuff[0] = '\0'; strncat(typbuff, "IPV6_HOPLIMIT", typlen-1);
diff --git a/xio-progcall.c b/xio-progcall.c
index e01aeae..13cd77d 100644
--- a/xio-progcall.c
+++ b/xio-progcall.c
@@ -229,14 +229,14 @@ int _xioopen_foxec(int xioflags,	/* XIO_RDONLY etc. */
 	       Warn2("unlockpt(%d): %s", ptyfd, strerror(errno));
 	    }
 #endif /* HAVE_UNLOCKPT */
-#if HAVE_PTSNAME	/* AIX, not Linux */
+#if HAVE_PROTOTYPE_LIB_ptsname	/* AIX, not Linux */
 	    if ((tn = Ptsname(ptyfd)) == NULL) {
 	       Warn2("ptsname(%d): %s", ptyfd, strerror(errno));
 	    }
-#endif /* HAVE_PTSNAME */
+#endif /* HAVE_PROTOTYPE_LIB_ptsname */
 	    if (tn == NULL) {
 	       if ((tn = Ttyname(ptyfd)) == NULL) {
-		  Warn2("ttyname(%d): %s", ptyfd, strerror(errno));
+		  Error2("ttyname(%d): %s", ptyfd, strerror(errno));
 	       }
 	    }
 	    ptyname[0] = '\0'; strncat(ptyname, tn, MAXPTYNAMELEN-1);
diff --git a/xio-pty.c b/xio-pty.c
index 5419c97..07aeec7 100644
--- a/xio-pty.c
+++ b/xio-pty.c
@@ -120,13 +120,13 @@ static int xioopen_pty(int argc, const char *argv[], struct opt *opts, int xiofl
 	    Warn2("unlockpt(%d): %s", ptyfd, strerror(errno));
 	 }
 #endif /* HAVE_UNLOCKPT */
-#if HAVE_PTSNAME	/* AIX, not Linux */
+#if HAVE_PROTOTYPE_LIB_ptsname	/* AIX, not Linux */
 	 if ((tn = Ptsname(ptyfd)) == NULL) {
 	    Warn2("ptsname(%d): %s", ptyfd, strerror(errno));
 	 } else {
 	    Notice1("PTY is %s", tn);
 	 }
-#endif /* HAVE_PTSNAME */
+#endif /* HAVE_PROTOTYPE_LIB_ptsname */
 	 if (tn == NULL) {
 	    if ((tn = Ttyname(ptyfd)) == NULL) {
 	       Warn2("ttyname(%d): %s", ptyfd, strerror(errno));
diff --git a/xio-socket.c b/xio-socket.c
index d53ade0..47a290a 100644
--- a/xio-socket.c
+++ b/xio-socket.c
@@ -1876,7 +1876,7 @@ xiolog_ancillary_socket(struct cmsghdr *cmsg, int *num,
    provide one in parameter ins to avoid creation of a dummy socket. ins must
    be <0 if it does not specify a socket fd. */
 char *xiogetifname(int ind, char *val, int ins) {
-#if !HAVE_IF_INDEXTONAME
+#if !HAVE_PROTOTYPE_LIB_if_indextoname
    int s;
    struct ifreq ifr;
 
@@ -1910,9 +1910,9 @@ char *xiogetifname(int ind, char *val, int ins) {
    if (ins < 0)  Close(s);
    strcpy(val, ifr.ifr_name);
    return val;
-#else /* HAVE_IF_INDEXTONAME */
+#else /* HAVE_PROTOTYPE_LIB_if_indextoname */
    return if_indextoname(ind, val);
-#endif /* HAVE_IF_INDEXTONAME */
+#endif /* HAVE_PROTOTYPE_LIB_if_indextoname */
 }
 
 
diff --git a/xioconfig.h b/xioconfig.h
index 03e4859..2cbab57 100644
--- a/xioconfig.h
+++ b/xioconfig.h
@@ -1,5 +1,5 @@
 /* source: xioconfig.h */
-/* Copyright Gerhard Rieger 2001-2008 */
+/* Copyright Gerhard Rieger */
 /* Published under the GNU General Public License V.2, see file COPYING */
 
 #ifndef __xioconfig_h_included
@@ -86,12 +86,12 @@
 #endif
 
 
-#if HAVE_DEV_PTMX && HAVE_GRANTPT && HAVE_UNLOCKPT && HAVE_PTSNAME
+#if HAVE_DEV_PTMX && HAVE_GRANTPT && HAVE_UNLOCKPT && HAVE_PROTOTYPE_LIB_ptsname
 #else
 #  undef HAVE_DEV_PTMX
 #endif
 
-#if HAVE_DEV_PTC /* && HAVE_GRANTPT && HAVE_UNLOCKPT && HAVE_PTSNAME */
+#if HAVE_DEV_PTC /* && HAVE_GRANTPT && HAVE_UNLOCKPT && HAVE_PROTOTYPE_LIB_ptsname */
 #else
 #  undef HAVE_DEV_PTC
 #endif