Support MinGW build with Clang, not just GCC

Fixes: #3270

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 05219ab..72f5f88 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -204,7 +204,8 @@
 function(glslang_set_link_args TARGET)
     # For MinGW compiles, statically link against the GCC and C++ runtimes.
     # This avoids the need to ship those runtimes as DLLs.
-    if(WIN32 AND ${CMAKE_CXX_COMPILER_ID} MATCHES "GNU")
+    # This is supported by GCC and Clang.
+    if(WIN32 AND NOT MSVC)
         set_target_properties(${TARGET} PROPERTIES
                               LINK_FLAGS "-static -static-libgcc -static-libstdc++")
     endif()