build: Share the all-local rule for linking libraries into the build dir

This consolidates how we link the libraries into the build directory.
It works for lib_LTLIBRARIES but not custom shared libraries like DRI
drivers or gallium state trackers which needs special casing (cf dri
mega drivers, for example)

Signed-off-by: Kristian Høgsberg <krh@bitplanet.net>
Reviewed-by: Matt Turner <mattst88@gmail.com>

install-lib-links.mk

@@ -0,0 +1,14 @@
+# Provide compatibility with scripts for the old Mesa build system for
+# a while by putting a link to the driver into /lib of the build tree.
+
+all-local : .libs/install-mesa-links
+
+.libs/install-mesa-links : $(lib_LTLIBRARIES)
+	$(MKDIR_P) $(top_builddir)/$(LIB_DIR)
+	for f in $(lib_LTLIBRARIES:%.la=.libs/%.so*); do	\
+		if test -h .libs/$$f; then			\
+			cp -d $$f $(top_builddir)/$(LIB_DIR);	\
+		else						\
+			ln -f $$f $(top_builddir)/$(LIB_DIR);	\
+		fi;						\
+	done && touch $@