Cygwin's GCC responds to the -m32 option, but it causes a compile error:
expected unqualified-id before ‘__int128’
inline __int128
If the project does not support the -m32 option, then it should be
removes so that using it causes a compile error.
Below is the changed needed to get through the compile with -m32:
$ diff
/usr/lib/gcc/x86_64-pc-cygwin/4.9.2/include/c++/x86_64-pc-cygwin/bits/c++config.h
/usr/lib/gcc/x86_64-pc-cygwin/4.9.2/include/c++/x86_64-pc-cygwin/bits/c++config.h.bu
1306,1308c1306
< #ifndef __CYGWIN32__ /* -m32 used on x86_64 */
< # define _GLIBCXX_USE_INT128 1
< #endif
---
> #define _GLIBCXX_USE_INT128 1
************
And this project really needs a bug tracker...
