build: do not assume glibc on linux

The whole IPv6 stack detection could need refactoring. But this
fixes the linux check to not assume glibc. Fixes build against
musl c-library.

Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>

diff --git a/configure.ac b/configure.ac
index 3dba3b3577134b42f0a3c65b6e6cf1c0cf1f9d27..f1df482b32851759ec4f0296ec7ea967219f053c 100755 (executable)
--- a/configure.ac
+++ b/configure.ac
@@ -1204,21 +1204,22 @@ dnl ----------
   if test "$zebra_cv_linux_ipv6" = "yes";then
     AC_MSG_CHECKING(for GNU libc >= 2.1)
     AC_DEFINE(HAVE_IPV6,1,Linux IPv6)
+    AC_DEFINE(LINUX_IPV6,1,Linux IPv6 stack)
+
     AC_EGREP_CPP(yes, [
 #include <features.h>
 #if __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1
   yes
 #endif], 
       [glibc=yes
-       AC_DEFINE(LINUX_IPV6,1,Linux IPv6 stack)
        AC_MSG_RESULT(yes)], 
       AC_MSG_RESULT(no)
     )
     RIPNGD="ripngd"
     OSPF6D="ospf6d"
     if test "$glibc" != "yes"; then
-      INCLUDES="-I/usr/inet6/include"
       if test x`ls /usr/inet6/lib/libinet6.a 2>/dev/null` != x;then
+         INCLUDES="-I/usr/inet6/include"
          LIB_IPV6="-L/usr/inet6/lib -linet6"
       fi
     fi