configure: Handle libnl-genl and libcap-ng consistent with other libs

Do not communicate any of the flags via the global
CFLAGS and LIBS, so that users are not confused when
overriding them on the command line.

Github: closes #586
Change-Id: I39a6f58b11b922f5dbd3e55a5bc8574eda8a83fe
Signed-off-by: Frank Lichtenheld <[email protected]>
Acked-by: Gert Doering <[email protected]>
Message-Id: <[email protected]>
URL: https://www.mail-archive.com/[email protected]/msg29282.html
Signed-off-by: Gert Doering <[email protected]>

configure.ac

@@ -802,8 +802,8 @@ if test "$enable_dco" != "no"; then
 					   AC_MSG_ERROR([libnl-genl-3.0 package not found or too old. Is the development package and pkg-config ${pkg_config_found} installed? Must be version 3.4.0 or newer for DCO])
 					  ]
 				)
-				CFLAGS="${CFLAGS} ${LIBNL_GENL_CFLAGS}"
-				LIBS="${LIBS} ${LIBNL_GENL_LIBS}"
+				OPTIONAL_LIBNL_GENL_CFLAGS="${LIBNL_GENL_CFLAGS}"
+				OPTIONAL_LIBNL_GENL_LIBS="${LIBNL_GENL_LIBS}"
 
 				AC_DEFINE(ENABLE_DCO, 1, [Enable shared data channel offload])
 				AC_MSG_NOTICE([Enabled ovpn-dco support for Linux])
@@ -843,16 +843,15 @@ dnl Depend on libcap-ng on Linux
 dnl
 case "$host" in
 	*-*-linux*)
-		# We require pkg-config
 		PKG_CHECK_MODULES([LIBCAPNG],
 				  [libcap-ng],
 				  [],
 				  [AC_MSG_ERROR([libcap-ng package not found. Is the development package and pkg-config ${pkg_config_found} installed?])]
 		)
 		AC_CHECK_HEADER([sys/prctl.h],,[AC_MSG_ERROR([sys/prctl.h not found!])])
 
-		CFLAGS="${CFLAGS} ${LIBCAPNG_CFLAGS}"
-		LIBS="${LIBS} ${LIBCAPNG_LIBS}"
+		OPTIONAL_LIBCAPNG_CFLAGS="${LIBCAPNG_CFLAGS}"
+		OPTIONAL_LIBCAPNG_LIBS="${LIBCAPNG_LIBS}"
 		AC_DEFINE(HAVE_LIBCAPNG, 1, [Enable libcap-ng support])
 	;;
 esac
@@ -1401,7 +1400,7 @@ fi
 
 # When testing a compiler option, we add -Werror to force
 # an error when the option is unsupported. This is not
-# required for gcc, but some compilers such as clang needs it.
+# required for gcc, but some compilers such as clang need it.
 AC_DEFUN([ACL_CHECK_ADD_COMPILE_FLAGS], [
     old_cflags="$CFLAGS"
     CFLAGS="$1 -Werror $CFLAGS"
@@ -1477,6 +1476,10 @@ AC_SUBST([OPTIONAL_DL_LIBS])
 AC_SUBST([OPTIONAL_SELINUX_LIBS])
 AC_SUBST([OPTIONAL_CRYPTO_CFLAGS])
 AC_SUBST([OPTIONAL_CRYPTO_LIBS])
+AC_SUBST([OPTIONAL_LIBCAPNG_CFLAGS])
+AC_SUBST([OPTIONAL_LIBCAPNG_LIBS])
+AC_SUBST([OPTIONAL_LIBNL_GENL_CFLAGS])
+AC_SUBST([OPTIONAL_LIBNL_GENL_LIBS])
 AC_SUBST([OPTIONAL_LZO_CFLAGS])
 AC_SUBST([OPTIONAL_LZO_LIBS])
 AC_SUBST([OPTIONAL_LZ4_CFLAGS])
@@ -1521,10 +1524,11 @@ PKG_CHECK_MODULES(
 AM_CONDITIONAL([ENABLE_UNITTESTS], [test "${enable_unit_tests}" = "yes" -a "${have_cmocka}" = "yes" ])
 AC_SUBST([ENABLE_UNITTESTS])
 
-TEST_LDFLAGS="${OPTIONAL_CRYPTO_LIBS} ${OPTIONAL_PKCS11_HELPER_LIBS}"
+TEST_LDFLAGS="${OPTIONAL_CRYPTO_LIBS} ${OPTIONAL_PKCS11_HELPER_LIBS} ${OPTIONAL_LIBCAPNG_LIBS}"
+TEST_LDFLAGS="${TEST_LDFLAGS} ${OPTIONAL_LIBNL_GENL_LIBS}"
 TEST_LDFLAGS="${TEST_LDFLAGS} ${OPTIONAL_LZO_LIBS} ${CMOCKA_LIBS}"
-TEST_CFLAGS="${OPTIONAL_CRYPTO_CFLAGS} ${OPTIONAL_PKCS11_HELPER_CFLAGS}"
-TEST_CFLAGS="${TEST_CFLAGS} ${OPTIONAL_LZO_CFLAGS}"
+TEST_CFLAGS="${OPTIONAL_CRYPTO_CFLAGS} ${OPTIONAL_PKCS11_HELPER_CFLAGS} ${OPTIONAL_LIBCAPNG_CFLAGS}"
+TEST_CFLAGS="${TEST_CFLAGS} ${OPTIONAL_LIBNL_GENL_CFLAGS} ${OPTIONAL_LZO_CFLAGS}"
 TEST_CFLAGS="${TEST_CFLAGS} -I\$(top_srcdir)/include ${CMOCKA_CFLAGS}"
 
 AC_SUBST([TEST_LDFLAGS])

src/openvpn/Makefile.am

@@ -24,6 +24,8 @@ AM_CPPFLAGS = \
 AM_CFLAGS = \
 	$(TAP_CFLAGS) \
 	$(OPTIONAL_CRYPTO_CFLAGS) \
+	$(OPTIONAL_LIBCAPNG_CFLAGS) \
+	$(OPTIONAL_LIBNL_GENL_CFLAGS) \
 	$(OPTIONAL_LZO_CFLAGS) \
 	$(OPTIONAL_LZ4_CFLAGS) \
 	$(OPTIONAL_PKCS11_HELPER_CFLAGS) \
@@ -147,6 +149,8 @@ openvpn_SOURCES = \
 openvpn_LDADD = \
 	$(top_builddir)/src/compat/libcompat.la \
 	$(SOCKETS_LIBS) \
+	$(OPTIONAL_LIBCAPNG_LIBS) \
+	$(OPTIONAL_LIBNL_GENL_LIBS) \
 	$(OPTIONAL_LZO_LIBS) \
 	$(OPTIONAL_LZ4_LIBS) \
 	$(OPTIONAL_PKCS11_HELPER_LIBS) \