crt: Implement sincos in C. #22

Job	Run time
llvm-mingw (ucrt)	22m 45s
gcc (msvcrt, i686)	19m 28s
gcc (ucrt, i686)	20m 5s
llvm-mingw (ucrtbase)	22m 47s
llvm-mingw (msvcrt)	24m 23s
gcc (ucrt, x86_64)	20m 9s
gcc (msvcrt, x86_64)	20m 25s
gcc-cross (ucrt, i686)	16m 42s
gcc-cross (ucrt, x86_64)	18m 5s
gcc-cross (msvcrt, x86_64)	18m 7s
gcc-cross (msvcrt, i686)	16m 31s
test-libcxx (x86_64, i686-w64-mingw32-)	1h 11m 13s
test-libcxx (x86_64)	1h 11m 14s
linux-test-cross-build-ffmpeg (aarch64)	4m 51s
linux-test-cross-build-ffmpeg (i686)	5m 0s
test-llvm-mingw (x86_64, ucrt)	3m 37s
test-llvm-mingw (x86_64, msvcrt)	3m 28s
linux-test-cross-build-ffmpeg (armv7)	5m 30s
linux-test-cross-build-ffmpeg (x86_64)	5m 55s
test-llvm-mingw (i686, ucrtbase)	3m 34s
test-llvm-mingw (x86_64, ucrtbase)	3m 40s
test-ffmpeg (x86_64)	17m 49s
test-llvm-mingw (i686, ucrt)	3m 39s
test-llvm-mingw (i686, msvcrt)	3m 34s
test-ffmpeg (i686)	17m 55s
test-gcc (ucrt, i686)	34s
test-gcc (msvcrt, x86_64)	40s
test-gcc (ucrt, x86_64)	39s
test-gcc (msvcrt, i686)	33s
	7h 22m 52s

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