Cygwin build fix: Fix linkage

Fix the way we make static convenience libraries, such as libmesa.a,
to be the same as linux etc.

Putting archives inside archives doesn't make the objects inside
the archive linkable, so use expand_archives() to get all the objects
inside an archive out again before linking.

Signed-off-by: Jon TURNEY <jon.turney@dronecode.org.uk>
Signed-off-by: Brian Paul <brianp@vmware.com>

bin/mklib

@@ -936,7 +936,14 @@ case $ARCH in
             if [ "${ALTOPTS}" ] ; then
                 OPTS=${ALTOPTS}
             fi
-            FINAL_LIBS=`make_ar_static_lib ${OPTS} 1 ${LIBNAME} ${OBJECTS}`
+
+            # expand .a into .o files
+            NEW_OBJECTS=`expand_archives ${LIBNAME}.obj $OBJECTS`
+
+            FINAL_LIBS=`make_ar_static_lib ${OPTS} 1 ${LIBNAME} ${NEW_OBJECTS}`
+
+            # remove temporary extracted .o files
+            rm -rf ${LIBNAME}.obj
         else
 	    OPTS="-shared -Wl,--enable-auto-image-base -Wl,-export-all -Wl,--out-implib=${LIBNAME}-${MAJOR}.dll.a"
             if [ "${ALTOPTS}" ] ; then