Compilation error when building gluegen from source

I'm getting a compiler error when attempting to build gluegen from source on Windows 10. I'm using mingw-w64 and the win32.c.compiler flag in gluegen.properties is set to mingw32. I see a series of errors during the 'gluegen.build.c.impl' phase of the form:

[cc] C:/Program Files/mingw-w64/x86_64-8.1.0-posix-seh-rt_v6-rev0/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: skipping incompatible C:/Program Files/mingw-w64/x86_64-8.1.0-posix-seh-rt_v6-rev0/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/lib/libmingw32.a when searching for -lmingw32

The error appears numerous times, also when searching for other arguments like -lgcc, -lgcc_eh, -lmoldname, -lmingwex, -lmsvcrt ... the list goes on.

Any idea what the problem is?

That's strange. I recently built on Windows 10 with msys2, here's how I did it (and no changes to JOGL's makefiles was required):

# Windows: get MSYS2 (file msys2-x86_64-20180531.exe) from https://www.msys2.org/
# double-click, install to C:\msys64
# run C:\msys64\msys2.exe, type "pacman -Syu", close window when it's done
# run C:\msys64\msys2.exe again, type "pacman -Su"
# run C:\msys64\msys2.exe again
    pacman -S mingw-w64-x86_64-binutils mingw-w64-x86_64-crt-git mingw-w64-x86_64-gcc mingw-w64-x86_64-gcc-libs mingw-w64-x86_64-gdb mingw-w64-x86_64-headers-git mingw-w64-x86_64-libmangle-git  mingw-w64-x86_64-libwinpthread-git mingw-w64-x86_64-make mingw-w64-x86_64-pkg-config mingw-w64-x86_64-tools-git mingw-w64-x86_64-winpthreads-git mingw-w64-x86_64-winstorecompat-git make
# add C:\msys64\usr\bin and C:\msys64\mingw64\bin to PATH

Fantastic - I followed your instructions and compiled again and I didn't have any problem at all. Thanks very much!