Remove warning for redefinition of M_PIf #25

Job	Run time
build-native-gcc	3m 21s
build-native-llvm	5m 24s
test-native-gcc	10m 27s
build-aarch64-gcc	5m 52s
test-native-llvm	7m 30s
build-aarch64-llvm	9m 38s
build-armhf-gcc	6m 27s
build-armhf-llvm	6m 22s
build-ppc64el-gcc	9m 14s
build-ppc64el-llvm	9m 30s
build-s390x-gcc	4m 23s
build-s390x-llvm	4m 4s
build-riscv64-llvm	3m 59s
test-aarch64-gcc (qemu_cpu: "max,sve=off")	18m 27s
test-aarch64-gcc (qemu_cpu: "max,sve=on,sve128=on")	23m 26s
test-aarch64-gcc (qemu_cpu: "max,sve=on,sve256=on")	25m 21s
test-aarch64-gcc (qemu_cpu: "max,sve=on,sve512=on")	28m 59s
test-armhf-gcc (qemu_cpu: "max")	15m 33s
test-armhf-llvm (qemu_cpu: "max")	13m 28s
test-ppc64el-gcc (qemu_cpu: "power10")	26m 40s
test-ppc64el-llvm (qemu_cpu: "power10")	27m 14s
test-s390x-gcc (qemu_cpu: "")	23m 23s
test-s390x-llvm (qemu_cpu: "")	21m 21s
test-riscv64-llvm (qemu_cpu: "rv64,zba=true,zbb=true,zbs=true,v=false")	3m 59s
test-riscv64-llvm (qemu_cpu: "rv64,zba=true,zbb=true,zbs=true,v=true,vlen=128,elen=64,vext_spec=v1.0")	16m 55s
test-riscv64-llvm (qemu_cpu: "rv64,zba=true,zbb=true,zbs=true,v=true,vlen=256,elen=64,vext_spec=v1.0")	20m 8s
test-riscv64-llvm (qemu_cpu: "rv64,zba=true,zbb=true,zbs=true,v=true,vlen=512,elen=64,vext_spec=v1.0")	34m 20s
	6h 25m 25s

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