diff -rauN z3-z3-4.8.7/src/util/mpz.cpp z3-z3-4.8.7-gnu-training_zeroes32-intrinsic-patch/src/util/mpz.cpp
--- z3-z3-4.8.7/src/util/mpz.cpp	2019-11-19 21:58:44.000000000 +0100
+++ z3-z3-4.8.7-gnu-training_zeroes32-intrinsic-patch/src/util/mpz.cpp	2019-12-13 10:31:15.080120693 +0100
@@ -72,6 +72,8 @@
 
 #if defined(_WINDOWS) && !defined(_M_ARM) && !defined(_M_ARM64)
 // _trailing_zeros32 already defined using intrinsics
+#elif defined(__GNUC__)
+// _trailing_zeros32 already defined using intrinsics
 #else
 inline uint32_t _trailing_zeros32(uint32_t x) {
     uint32_t r = 0;