build-sys: link with libgsf optionnally

Makefile.am

@@ -8,9 +8,9 @@ MAINTAINERCLEANFILES = \
 	$(srcdir)/config.guess $(srcdir)/config.sub
 EXTRA_DIST = .gitignore
 
-AM_CFLAGS = $(OPENSSL_CFLAGS) $(OPTIONAL_LIBCURL_CFLAGS)
+AM_CFLAGS = $(GSF_CFLAGS) $(OPENSSL_CFLAGS) $(OPTIONAL_LIBCURL_CFLAGS)
 
 bin_PROGRAMS = osslsigncode
 
 osslsigncode_SOURCES = osslsigncode.c
-osslsigncode_LDADD = $(OPENSSL_LIBS) $(OPTIONAL_LIBCURL_LIBS)
+osslsigncode_LDADD = $(GSF_LIBS) $(OPENSSL_LIBS) $(OPTIONAL_LIBCURL_LIBS)

config.h.in

@@ -88,6 +88,9 @@
 /* Version number of package */
 #undef VERSION
 
+/* Have libgsf? */
+#undef WITH_GSF
+
 /* Define to 1 if on MINIX. */
 #undef _MINIX
 

configure.ac

@@ -68,6 +68,20 @@ AC_CHECK_LIB(
 	[DL_LIBS="-ldl"]
 )
 
+AC_ARG_WITH([gsf],
+        AS_HELP_STRING([--without-gsf], [Ignore presence of libgsf and disable it])
+)
+AS_IF([test "x$with_gsf" != "xno"],
+        [PKG_CHECK_MODULES([GSF], [libgsf-1], [have_gsf=yes], [have_gsf=no])],
+        [have_gsf=no]
+)
+AS_IF([test "x$have_gsf" = "xyes"],
+        [AC_DEFINE([WITH_GSF], 1, [Have libgsf?])],
+        [AS_IF([test "x$with_gsf" = "xyes"],
+                [AC_MSG_ERROR([libgsf requested but not found])])]
+)
+
+
 PKG_CHECK_MODULES(
 	[OPENSSL],
 	[libcrypto >= 0.9.8],