MinGW: libtool falls back to static lib unless -no-undefined given

--- a/src/Makefile.in	2013-03-29 19:11:27.944919859 +0100
+++ b/src/Makefile.in	2013-03-29 20:05:02.140892243 +0100
@@ -507,7 +507,7 @@
 	$(am__append_21) $(am__append_22) $(am__append_23) \
 	$(am__append_24) $(am__append_25) $(am__append_26) \
 	$(am__append_27) $(am__append_28)
-libraptor2_la_LDFLAGS = -version-info @RAPTOR_LIBTOOL_VERSION@ \
+libraptor2_la_LDFLAGS = -version-info @RAPTOR_LIBTOOL_VERSION@ -no-undefined \
 @RAPTOR_LDFLAGS@ $(MEM_LIBS)
 
 libraptor2_la_LIBADD = @LTLIBOBJS@