plugin/core: autotools: add linking to xdot

E.g. plugin/core/gvrender_core_dot.c uses parseXDot from
lib/xdot/xdot.c.

Fixes these errors when building with Cygwin from the portable source
produced by the Ubuntu 18.03 runner in CI:

/cygdrive/c/GitLab-Runner/builds/magjac/graphviz/graphviz-2.49.1~dev.20210915.2014/plugin/core/gvrender_core_json.c:313: undefined reference to `parseXDot'
/usr/lib/gcc/x86_64-pc-cygwin/11/../../../../x86_64-pc-cygwin/bin/ld: /cygdrive/c/GitLab-Runner/builds/magjac/graphviz/graphviz-2.49.1~dev.20210915.2014/plugin/core/gvrender_core_json.c:331: undefined reference to `freeXDot'

For some reason, this error did not show up when building using a
build system generated on Cygwin with autogen.sh.

diff --git a/plugin/core/Makefile.am b/plugin/core/Makefile.am
index 0893cc5bd76395040ec7f6f743d2e7ef41692469..3cad8cc4f4bdb8266f3fb13f43a09a0d4380b619 100644 (file)
--- a/plugin/core/Makefile.am
+++ b/plugin/core/Makefile.am
@@ -38,7 +38,8 @@ libgvplugin_core_la_LDFLAGS = -version-info @GVPLUGIN_VERSION_INFO@
 libgvplugin_core_la_SOURCES = $(libgvplugin_core_C_la_SOURCES)
 libgvplugin_core_la_LIBADD = $(top_builddir)/lib/gvc/libgvc.la \
                                $(top_builddir)/lib/cgraph/libcgraph.la \
-                               $(top_builddir)/lib/cdt/libcdt.la
+                               $(top_builddir)/lib/cdt/libcdt.la \
+                               $(top_builddir)/lib/xdot/libxdot.la
 
 gvrender_core_ps.o gvrender_core_ps.lo: ps.h