Fix building on 32-bit systems

[ItalyPaleAle]

Builds on 32-bit systems are failing:

 /go/pkg/mod/github.com/lestrrat-go/jwx/v2@v2.0.21/jwt/openid/birthdate.go:69:7: math.MaxInt64 (untyped int constant 9223372036854775807) overflows int

This changes how 32-bit systems are detected in a way that doesn't cause the error. Although this does remove 16-bit systems from the case, the Go compiler does not support any 16-bit system at present (and it's very unlikely it ever will).

[codecov]

Codecov Report

Attention: Patch coverage is 33.33333% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 75.10%. Comparing base (0a15b4d) to head (5a3d7f0).
Report is 73 commits behind head on develop/v2.

Files	Patch %	Lines
jwt/openid/birthdate.go	33.33%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@              Coverage Diff               @@
##           develop/v2    #1127      +/-   ##
==============================================
+ Coverage       72.00%   75.10%   +3.09%     
==============================================
  Files              93       95       +2     
  Lines           13795    11941    -1854     
==============================================
- Hits             9933     8968     -965     
+ Misses           3044     2157     -887     
+ Partials          818      816       -2     

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[ItalyPaleAle]

I'm not sure how to appease CodeQL at this point. It's a false positive but nothing I do seems to make it happy.

[lestrrat]

Thanks, but I'm a bit reluctant to merge something that I can't test.
Would you be able to provide a 32-bit environment smoke test, possibly by running a container or some such in GitHub Actions?

[ItalyPaleAle]

Sadly GH Actions runs on amd64, and Docker runs 64-bit containers on 64-bit operating systems like our laptops.

Simplest thing you can do to test this, if you're on a Linux box with qemu-system-arm and qemu-user-binfmt installed (this will be very slow):

cd examples
GOOS=linux GOARCH=arm GOARM=7 go test

The go test command above will fail when cross-compiling for armv7 (32-bit), during the build stage, with this error:

# github.com/lestrrat-go/jwx/v2/jwt/openid
../jwt/openid/birthdate.go:69:7: math.MaxInt64 (untyped int constant 9223372036854775807) overflows int

If you check out this PR, you'll see the build passes and the tests (running using emulation) work.

[lestrrat]

@ItalyPaleAle Well, I wanted to make sure I get to test and fix the CodeQL problem.
Also, I'm not talking about you or this PR, but I've had my share of I-trusted-the-PR-without-much-scrutiny-and-it-bit-me-later types of problems, so I'm being cautious here :)

Anyways. I see how you verified the 32-bit compilation, so I've dug in and isolated the problem down to #1129 . This way there's no CodeQL shenanigans, and I think Go on 32-bit arch can compile it. Does this work for you?

[ItalyPaleAle]

Did not take it personally at all, your request was very valid and reasonable :)

#1129 LGTM and I think will fix the problem while making CodeQL happy. I'll close this PR. Thanks!