If you want it to be possible to cross-compile your program to MinGW and you use Libtool, you need to put:
in your configure.ac. This sets the correct names for the
AS tools for the build.
If you are building a library, you will also need to pass
-no-undefined to make sure Libtool produces a DLL for your
library. From a Makefile.am:
libgsasl_la_LDFLAGS += -no-undefined