change compiler

Author: skvark

travis/toolchain_macos.cmake

@@ -3,7 +3,7 @@ SET(CMAKE_SYSTEM_VERSION 16)
 SET(CMAKE_SYSTEM_PROCESSOR x86_64)
 SET(ARCH x86_64)
 
-set(CMAKE_C_COMPILER clang)
+set(CMAKE_C_COMPILER gcc)
 set(CMAKE_C_COMPILER_TARGET ${arch})
-set(CMAKE_CXX_COMPILER clang++)
+set(CMAKE_CXX_COMPILER g++)
 set(CMAKE_CXX_COMPILER_TARGET ${arch})