Makes Clang compilations via Ninja on Windows define _DLL only for shared CRT...

Makes Clang compilations via Ninja on Windows define _DLL only for shared CRT builds, as one would already expect from MSVC builds. (Previously, static Clang/Ninja builds on Windows also implicitly defined _DLL, which was problematic.)

PiperOrigin-RevId: 479113168
Change-Id: I252d9be90fd33df75dab922e62b197208830d124

googletest/cmake/internal_utils.cmake

@@ -21,8 +21,9 @@ endif (POLICY CMP0054)
 # This must be a macro(), as inside a function string() can only
 # update variables in the function scope.
 macro(fix_default_compiler_settings_)
-  if (MSVC)
-    # For MSVC, CMake sets certain flags to defaults we want to override.
+  if (CMAKE_CXX_COMPILER_ID MATCHES "MSVC|Clang")
+    # For MSVC and Clang, CMake sets certain flags to defaults we want to
+    # override.
     # This replacement code is taken from sample in the CMake Wiki at
     # https://gitlab.kitware.com/cmake/community/wikis/FAQ#dynamic-replace.
     foreach (flag_var
@@ -39,6 +40,10 @@ macro(fix_default_compiler_settings_)
         # on CRT DLLs being available. CMake always defaults to using shared
         # CRT libraries, so we override that default here.
         string(REPLACE "/MD" "-MT" ${flag_var} "${${flag_var}}")
+
+        # When using Ninja with Clang, static builds pass -D_DLL on Windows.
+        # This is incorrect and should not happen, so we fix that here.
+        string(REPLACE "-D_DLL" "" ${flag_var} "${${flag_var}}")
       endif()
 
       # We prefer more strict warning checking for building Google Test.