Run ranlib on libgit2.a after archiving it

Some linkers require ranlib to build a symbol table on the archive
in order to work with it.  Most platforms that don't have this
requirement permit ranlib as a noop.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Makefile

 all::
 
 DOXYGEN = doxygen
+RANLIB  = ranlib
 
 prefix=/usr/local
 
@@ -71,6 +72,7 @@ $(OBJS): $(HDRS)
 $(GIT_LIB): $(OBJS)
 	rm -f $(LIB)
 	$(AR) cr $(GIT_LIB) $(OBJS)
+	$(RANLIB) $(GIT_LIB)
 
 T_HDR         = tests/test_lib.h
 T_LIB         = tests/test_lib.o