Problem: -lssp causes build failure on Solaris

Solution: add -lssp on Solaris only when libsodium is enabled and has
been found. Also disable pedantic and Werror, as libsodium headers
use pragma diagnostic which are not available in gcc 3.4.

configure.ac

@@ -182,8 +182,6 @@ case "${host_os}" in
         if test "x$solaris_has_atomic" = "xno"; then
             AC_DEFINE(ZMQ_FORCE_MUTEXES, 1, [Force to use mutexes])
         fi
-        # ssp library is required for libsodium on Solaris-like systems
-        LDFLAGS="-lssp $LDFLAGS"
         CPPFLAGS="$CPPFLAGS -Wno-long-long"
         ;;
     *freebsd*)
@@ -419,6 +417,8 @@ elif test "x$with_libsodium" = "xyes"; then
     case "${host_os}" in
         *solaris*)
             LDFLAGS="-lssp $LDFLAGS"
+            libzmq_pedantic="no"
+            libzmq_werror="no"
         ;;
     esac
 else