cygwinccompiler: Get the compilers from sysconfig #62

Job	Run time
collateral (diffcov)	49s
ci_setuptools (3.10, ubuntu-latest)	3m 38s
test_cygwin (39, windows-latest)	5m 4s
collateral (docs)	33s
test (3.8, ubuntu-latest)	1m 4s
test_msys2_mingw (mingw64, x86_64, gcc, g++)	2m 42s
test (3.8, macos-latest)	1m 13s
test_msys2_mingw (mingw32, i686, gcc, g++)	2m 38s
test (3.8, windows-latest)	2m 16s
test_msys2_mingw (ucrt64, ucrt-x86_64, gcc, g++)	2m 27s
test (3.12, ubuntu-latest)	42s
test_msys2_mingw (clang64, clang-x86_64, clang, clang++)	2m 37s
test (3.12, macos-latest)	1m 3s
test (3.12, windows-latest)	2m 7s
test (3.9, ubuntu-latest)	44s
test (3.10, ubuntu-latest)	38s
test (3.11, ubuntu-latest)	38s
test (pypy3.10, ubuntu-latest)	1m 47s
check	1s
release	0s
	32m 41s

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