Fix linking with libm

Fixes using clang's MSVC ABI.

Fixes: #728

Author: Oliver-makes-code

CMakeLists.txt

@@ -212,7 +212,10 @@ find_package(Threads)
 if(NOT CMAKE_SYSTEM_NAME STREQUAL "WASI")
     list(APPEND qjs_libs ${CMAKE_THREAD_LIBS_INIT})
 endif()
-if(NOT MSVC)
+
+# try to find libm
+find_library(M_LIBRARIES m)
+if(M_LIBRARIES OR CMAKE_C_COMPILER_ID STREQUAL "TinyCC")
     list(APPEND qjs_libs m)
 endif()