CMake: Fix using Cotire for precompiled headers

Cotire doesn't work when $<COMPILE_LANGUAGE:CXX> is used.

build/cmake/functions.cmake

@@ -154,10 +154,14 @@ function(wx_set_common_target_properties target_name)
             )
         endif()
 
-        target_compile_options(${target_name} PRIVATE
-            ${common_gcc_clang_compile_options}
-            $<$<COMPILE_LANGUAGE:CXX>:${common_gcc_clang_cpp_compile_options}>
-        )
+        # Using $<COMPILE_LANGUAGE:CXX> breaks cotire:
+        # Evaluation file to be written multiple times with different content.
+        if(NOT USE_COTIRE)
+            target_compile_options(${target_name} PRIVATE
+                ${common_gcc_clang_compile_options}
+                $<$<COMPILE_LANGUAGE:CXX>:${common_gcc_clang_cpp_compile_options}>
+            )
+        endif()
     endif()
 
     if(wxUSE_NO_RTTI)

build/cmake/init.cmake

@@ -665,5 +665,7 @@ if((wxBUILD_PRECOMP STREQUAL "ON" AND CMAKE_VERSION VERSION_LESS "3.16") OR (wxB
     if(NOT RESULT_VAR)
         message(WARNING "precompiled header (PCH) test failed, it will be turned off")
         wx_option_force_value(wxBUILD_PRECOMP OFF)
+    else()
+        set(USE_COTIRE ON)
     endif()
 endif()

build/cmake/pch.cmake

@@ -20,7 +20,7 @@ endif()
 macro(wx_target_enable_precomp target_name prec_header)
     if(wxBUILD_PRECOMP)
         target_compile_definitions(${target_name} PRIVATE WX_PRECOMP)
-        if(CMAKE_VERSION VERSION_LESS "3.16" OR wxBUILD_PRECOMP STREQUAL "COTIRE")
+        if(USE_COTIRE)
             set_target_properties(${target_name} PROPERTIES COTIRE_CXX_PREFIX_HEADER_INIT ${prec_header})
             set_target_properties(${target_name} PROPERTIES COTIRE_ADD_UNITY_BUILD FALSE)
             cotire(${target_name})