Building nxproxy with Cygwin tools for NXLogin

I used the default Cygwin gcc toolchain as of 2012-03-09.

I applied the following changes to the source, which enable use of libpng12 and xauth:

# nxcomp-3.5.0-2
echo '
388c388,389
<     LIBS="-lstdc++ -lpng -ljpeg -lz"
---
>     CXXFLAGS="-I/usr/include/libpng12 $CXXFLAGS"
>     LIBS="-lstdc++ -lpng12 -ljpeg -lz"
' | patch configure.in
echo '229c229
<   #if defined(__CYGWIN32__) || defined(__APPLE__)
---
>   #if defined(__APPLE__)' | patch Auth.cpp
autoconf-2.13
./configure
make
cp -p cygXcomp.dll ..

# nxproxy-3.5.0-1
echo '
162c162
<     LIBS="$LIBS -L../nxcomp -lXcomp -lstdc++ -Wl,-e,_mainCRTStartup -ljpeg -lpng -lz"
---
>     LIBS="$LIBS -L../nxcomp -lXcomp -lstdc++ -Wl,-e,_mainCRTStartup -ljpeg -lpng12 -lz"
' | patch configure.in
autoconf-2.13
./configure
make
cp -p nxproxy.exe ..

Afterwards, grab the two binaries cygXcomp.dll and nxproxy.exe and put them in the contrib/nx folder of the NXLogin program directory.