../src/util/mpz.cpp:57:30: error: definition of ‘uint32_t __builtin_ctz(uint32_t)’ ambiguates built-in declaration ‘int __builtin_ctz(unsigned int)’
 #define _trailing_zeros32(X) __builtin_ctz(X)
                              ^~~~~~~~~~~~~
../src/util/mpz.cpp:76:17: note: in expansion of macro ‘_trailing_zeros32’
 inline uint32_t _trailing_zeros32(uint32_t x) {
                 ^~~~~~~~~~~~~~~~~
make: *** [Makefile:216: util/mpz.o] Error 1
make: *** Waiting for unfinished jobs....
make: Leaving directory '/af/build/user/z3/src/z3-z3-4.8.7/build'
>>> ERROR: z3: build failed

Upstream issues:
https://github.com/Z3Prover/z3/issues/2727
https://github.com/Z3Prover/z3/issues/2776