This is to test for the following issue:
  #439

Error is:

In file included from C:/Ruby34-x64/include/ruby-3.4.0/ruby/defines.h:74,
                 from C:/Ruby34-x64/include/ruby-3.4.0/ruby/ruby.h:25,
                 from C:/Ruby34-x64/include/ruby-3.4.0/ruby.h:38,
                 from conftest.c:1:
C:/msys64/ucrt64/include/stralign.h: In function 'ua_CharUpperW':
C:/Ruby34-x64/include/ruby-3.4.0/ruby/backward/2/bool.h:31:15: error: 'true' undeclared (first use in this function)
   31 | # define TRUE true
      |               ^~~~
In file included from C:/msys64/ucrt64/include/windows.h:114,
                 from C:/msys64/ucrt64/include/winsock2.h:23,
                 from C:/Ruby34-x64/include/ruby-3.4.0/ruby/win32.h:36,
                 from C:/Ruby34-x64/include/ruby-3.4.0/ruby/internal/dosish.h:38,
                 from C:/Ruby34-x64/include/ruby-3.4.0/ruby/defines.h:78:
C:/msys64/ucrt64/include/stralign.h:1:1: note: 'true' is defined in header '<stdbool.h>'; this is probably fixable by adding '#include <stdbool.h>'
  +++ |+#include <stdbool.h>
    1 | /**