libc: replace musl's and MinGW's trigonometric functions with compiler_rt's

[papparapa]

Part of #2879.
According to the instruction, this PR removes some musl files, including the following functions:

• musl
  • sin
  • sinf
  • cos
  • cosf
  • sincos
  • sincosf
  • tan
  • tanf
• MinGW (added after review)
  • sinf
  • cosf
  • sincos
  • sincosf
  • tanf

I confirmed that running zig build test-modules and zig-libc-test raised no errors during the trigonometric function tests.
zig-libc-test revealed some discrepancies between the results of long double trigonometric functions in compiler_rt and musl. Therefore, this PR is restricted to float and double functions.

[alexrp]

It seems like we also have

• cosf
• sincos (includes sincosl?)
• sincosf
• sinf
• tanf

in lib/libc/mingw.

[papparapa]

When deleting musl files, I was able to run the deletion after confirming with zig-libc-test that the function behavior did not change.
However, I am not sure what policy I can use to delete MinGW files.
The behavior of compiler_rt's sin function and musl's sin function are consistent, but MinGW's sin function may not be.
Do I need to make sure that the behavior of compiler_rt's sin function and MinGW's sin function match?
Or, even if the behavior does not match, can we assume that musl's sin function (compiler_rt's sin function) behavior is more appropriate and remove MinGW's sin function?

[alexrp]

Do I need to make sure that the behavior of compiler_rt's sin function and MinGW's sin function match?

I don't think so. musl tends to be pretty good about math functions, so until we have evidence to the contrary, let's assume that it's a good baseline for math functions for all static libcs.

[papparapa]

Thanks, I deleted the MinGW files with relief. (71ff383)
In lib/libc/mingw/math/arm/sincos.S and lib/libc/mingw/math/arm64/sincos.S, I removed only the sincos symbol.
It will not be too late to remove MinGW's sincosl at the same time as musl.

[andrewrk]

Nice, thank you

[andrewrk]

Sorry @alexrp, I didn't notice you had assigned yourself or I would have left it in your hands.

[alexrp]

No worries, I'm not calling dibs or anything. 🙂