LDFLAGS -no-undefined flag should be added like all other X.org libraries

CC @alanc

https://github.com/conda-forge/xorg-libxxf86vm-feedstock/commit/7c758477ff

From looking at the other X.org libraries, it seems that they simple include the -no-undefined flag in the LDFLAGS definitions for their libraries in Makefile.am. This package omits it, presumably because no one builds it on Windows. Patching the source file to add the flag fixes the build. In principle this fix should be submitted upstream, but this library looks to be pretty much unmaintained these days.

Hi, we are downstream package maintainers, and to build (unofficially) on Windows, the -no-undefined flag in the LDFLAGS definitions for in Makefile.am should be added.

Thanks.