#18339 was about adding a SWIGFLAGS environment variable similar to CFLAGS, for flags to pass to SWIG.

Would that fix your problem?

We didn't implement #18339 because nobody provided a compelling use case. What is your compelling use case? The SWIG libraries themselves don't use SWIGWORDSIZE64; what would you use it for?

I believe it would fix. SWIG tries to determine the word size (see https://github.com/swig/swig/blob/master/Lib/swigarch.i) and this can also be explicit defined if one sets -DSWIGWORDSIZE32 or -DSWIGWORDSIZE64.

The main problem here is that if this is not set and any of the defines used in swigarch (namely __WORDSIZE, __x86_64 and __x86_64__) are set, swig will automatically set the word size as 32.

This is a problem for some x64 architectures as swig wrongly generates bindings considering a word size of 32 instead of 64 (see https://github.com/swig/swig/blob/master/Lib/stdint.i).

What I am currently doing as a workaround is to generate a swig interface containing these defines (obtained from cc) every time I build my application, however I feel like go should let us pass this kind of flags instead.