fxruby gem won't compile

[jpearl01]

I've built a little fxruby (a gui library) app, and I'm having trouble getting it to compile - this is possibly related to issue #125

This app exists here, if you would like to test: https://github.com/jpearl01/qs_automation

Here is the gem_make.out file:

current directory: C:/Users/Josh/AppData/Local/Temp/rubyc/ruby_install/lib/ruby/gems/2.7.0/gems/fxruby-1.6.43/ext/fox16_c
C:/Users/Josh/AppData/Local/Temp/rubyc/ruby_install/bin/ruby.exe -I C:/Users/Josh/AppData/Local/Temp/rubyc/ruby_install/lib/ruby/2.7.0 -r ./siteconf20201211-37268-83tiev.rb extconf.rb
checking for fox per pkg-config... no
checking for fxscintilla per pkg-config... no
checking for fxscintilla on Ubuntu with missing libfxscintilla.so link... no
checking for fxscintilla build... no
checking for sys/time.h... no
checking for signal.h... yes
checking for deflate() in z.lib... no
checking for png_create_read_struct() in png.lib... no
checking for jpeg_mem_init() in jpeg.lib... no
checking for TIFFSetErrorHandler() in tiff.lib... no
checking for XftInit() in Xft.lib... no
checking for XShmQueryVersion() in Xext.lib... no
checking for XFindContext() in X11.lib... no
checking for glXCreateContext() in GL.lib... no
checking for gluNewQuadric() in GLU.lib... no
checking for thread local variables... no
checking for rb_during_gc()... no
creating extconf.h
creating Makefile

current directory: C:/Users/Josh/AppData/Local/Temp/rubyc/ruby_install/lib/ruby/gems/2.7.0/gems/fxruby-1.6.43/ext/fox16_c
nmake "DESTDIR=" clean

Microsoft (R) Program Maintenance Utility Version 14.28.29335.0
Copyright (C) Microsoft Corporation.  All rights reserved.


current directory: C:/Users/Josh/AppData/Local/Temp/rubyc/ruby_install/lib/ruby/gems/2.7.0/gems/fxruby-1.6.43/ext/fox16_c
nmake "DESTDIR="

Microsoft (R) Program Maintenance Utility Version 14.28.29335.0
Copyright (C) Microsoft Corporation.  All rights reserved.

generating fox16_c-x64-mswin64_140.def
compiling FXRbApp.cpp
FXRbApp.cpp
C:\Users\Josh\AppData\Local\Temp\rubyc\ruby_install\include\ruby-2.7.0\x64-mswin64_140\ruby/config.h(22): warning C4117: macro name '_INTEGRAL_MAX_BITS' is reserved, '#define' ignored
C:\Users\Josh\AppData\Local\Temp\rubyc\ruby_install\lib\ruby\gems\2.7.0\gems\fxruby-1.6.43\ext\fox16_c\include\FXRbCommon.h(72): fatal error C1083: Cannot open include file: 'fx.h': No such file or directory
NMAKE : fatal error U1077: '"C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.28.29333\bin\HostX64\x64\cl.EXE"' : return code '0x2'
Stop.

make failed, exit code 2

In the output error message this hint appears:

An error occurred while installing fxruby (1.6.43), and Bundler cannot continue.
Make sure that `gem install fxruby -v '1.6.43' --source 'http://rubygems.org/'`
succeeds before bundling.

However, this command does complete successfully for me:

>gem install fxruby -v '1.6.43' --source 'http://rubygems.org/'
Successfully installed fxruby-1.6.43-x64-mingw32
Parsing documentation for fxruby-1.6.43-x64-mingw32
Done installing documentation for fxruby after 2 seconds
1 gem installed