Add CMake build support for IBM Z #6042

Job	Run time
neoverse_build	7m 40s
build (ubuntu-latest, gfortran, make)	23m 8s
build (ubuntu-latest, gfortran, cmake)	46m 6s
build (macos-latest, gfortran, cmake)	36m 39s
build (ubuntu-latest, flang, cmake)	14m 41s
cross_build (mips64el, mips64el-linux-gnuabi64, DYNAMIC_ARCH=1 TARGET=GENERIC)	4m 19s
build (ubuntu-latest, flang, make)	5m 1s
build (macos-latest, gfortran, make)	5m 51s
msys2 (CLANG64, int32, Release)	15m 22s
msys2 (UCRT64, int32, None, mingw-w64-ucrt-x86_64, fc)	11m 57s
msys2 (UCRT64, int32, Release)	13m 28s
cross_build (riscv64, riscv64-linux-gnu, TARGET=RISCV64_GENERIC)	2m 48s
cross_build (mipsel, mipsel-linux-gnu, TARGET=MIPS1004K)	3m 37s
msys2 (MINGW32, int32, Release)	15m 0s
cross_build (alpha, alpha-linux-gnu, TARGET=EV4)	3m 25s
msys2 (UCRT64, int64, Release)	13m 44s
msys2 (CLANG64, int64, Release)	15m 11s
	3h 57m 57s

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