Define __EXTENSIONS__ on Solaris. Fixes posixmodule error in bug #232787.
diff --git a/configure.in b/configure.in
index 92a5b46..0818a9c 100644
--- a/configure.in
+++ b/configure.in
@@ -194,8 +194,13 @@
     case $CC in
     cc) CC="$CC -Wl,-Bexport";;
     esac;;
+SunOS*)
+    # Some functions have a prototype only with that define, e.g. confstr
+    AC_DEFINE(__EXTENSIONS__)
+    ;;
 esac
 
+
 AC_SUBST(LIBRARY)
 AC_MSG_CHECKING(LIBRARY)
 if test -z "$LIBRARY"