Build system: Check for “libiptc/libip6tc.h” and “linux/netfilter/x_tables.h”, too.

Apparently “linux/netfilter/x_tables.h” is not available with older
kernels which leads to build fails there:
-- 8< --
 In file included from libiptc.c:47,
                  from libip4tc.c:136:
 xtables.h:24:38: linux/netfilter/x_tables.h: No such file or directory
-- >8 --

diff --git a/configure.in b/configure.in
index 092fbd0..c076e77 100644 (file)
--- a/configure.in
+++ b/configure.in
@@ -1453,29 +1453,32 @@ SAVE_CPPFLAGS="$CPPFLAGS"
 SAVE_LDFLAGS="$LDFLAGS"
 CPPFLAGS="$CPPFLAGS $LIBIPTC_CPPFLAGS"
 LDFLAGS="$LDFLAGS $LIBIPTC_LDFLAGS"
-if test "x$with_libiptc" = "xyes"
+# check whether the header file for libiptc is available.
+if test "x$with_libiptc" = "xyes" && test "x$with_own_libiptc" = "xno"
 then
-       AC_CHECK_HEADERS(linux/netfilter_ipv4/ip_tables.h linux/netfilter_ipv6/ip6_tables.h, [],
+       AC_CHECK_HEADERS(libiptc/libiptc.h,
        [
-               with_libiptc="no (Linux iptables headers not found)"
-               with_own_libiptc="no"
+               AC_DEFINE(HAVE_LIBIPTC_LIBIPTC_H, 1, [Define to 1 if you have the <libiptc/libiptc.h> header file.])
        ],
        [
-#include "$srcdir/src/owniptc/ipt_kernel_headers.h"
+               with_libiptc="yes"
+               with_own_libiptc="yes"
        ])
-
 fi
 if test "x$with_libiptc" = "xyes" && test "x$with_own_libiptc" = "xno"
 then
-       AC_CHECK_HEADERS(libiptc/libiptc.h,
+       AC_CHECK_HEADERS(libiptc/libip6tc.h,
        [
-               AC_DEFINE(HAVE_LIBIPTC_LIBIPTC_H, 1, [Define to 1 if you have the <libiptc/libiptc.h> header file.])
+               AC_DEFINE(HAVE_LIBIPTC_LIBIP6TC_H, 1, [Define to 1 if you have the <libiptc/libip6tc.h> header file.])
        ],
        [
                with_libiptc="yes"
                with_own_libiptc="yes"
        ])
 fi
+# If the header file is available, check for the required type declaractions.
+# They may be missing in old versions of libiptc. In that case, they will be
+# declared in the iptables plugin.
 if test "x$with_libiptc" = "xyes" && test "x$with_own_libiptc" = "xno"
 then
        AC_CHECK_TYPES([iptc_handle_t, ip6tc_handle_t], [], [],
@@ -1489,6 +1492,7 @@ then
 #endif
        ])
 fi
+# Check for the iptc_init symbol in the library.
 if test "x$with_libiptc" = "xyes" && test "x$with_own_libiptc" = "xno"
 then
        AC_CHECK_LIB(iptc, iptc_init,
@@ -1500,6 +1504,19 @@ then
                with_own_libiptc="yes"
        ])
 fi
+# The system wide version failed for some reason. Check if we have the required
+# headers to build the shipped version.
+if test "x$with_libiptc" = "xyes" && test "x$with_own_libiptc" = "xyes"
+then
+       AC_CHECK_HEADERS(linux/netfilter_ipv4/ip_tables.h linux/netfilter_ipv6/ip6_tables.h linux/netfilter/x_tables.h, [],
+       [
+               with_libiptc="no (Linux iptables headers not found)"
+               with_own_libiptc="no"
+       ],
+       [
+#include "$srcdir/src/owniptc/ipt_kernel_headers.h"
+       ])
+fi
 AM_CONDITIONAL(BUILD_WITH_LIBIPTC, test "x$with_libiptc" = "xyes")
 AM_CONDITIONAL(BUILD_WITH_OWN_LIBIPTC, test "x$with_own_libiptc" = "xyes")
 if test "x$with_libiptc" = "xyes"