enable_language: Allow CMakeDetermine<LANG>Compiler module to fail early

If the module reports a FATAL_ERROR, skip the rest of the steps to
enable the language to avoid unnecessary following error messages.

Source/cmGlobalGenerator.cxx

@@ -564,6 +564,10 @@ cmGlobalGenerator::EnableLanguage(std::vector<std::string>const& languages,
         cmSystemTools::Error("Could not find cmake module file: ",
                              determineCompiler.c_str());
         }
+      if (cmSystemTools::GetFatalErrorOccured())
+        {
+        return;
+        }
       needTestLanguage[lang] = true;
       // Some generators like visual studio should not use the env variables
       // So the global generator can specify that in this variable

Tests/RunCMake/Languages/DetermineFail-result.txt

@@ -0,0 +1 @@
+1

Tests/RunCMake/Languages/DetermineFail-stderr.txt

@@ -0,0 +1,5 @@
+^CMake Error at Modules/CMakeDetermineFailCompiler.cmake:[0-9]+ \(message\):
+  This language is not supported.
+Call Stack \(most recent call first\):
+  DetermineFail.cmake:[0-9]+ \(enable_language\)
+  CMakeLists.txt:[0-9]+ \(include\)

Tests/RunCMake/Languages/DetermineFail.cmake

@@ -0,0 +1,2 @@
+list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/Modules)
+enable_language(Fail)

Tests/RunCMake/Languages/Modules/CMakeDetermineFailCompiler.cmake

@@ -0,0 +1 @@
+message(FATAL_ERROR "This language is not supported.")

Tests/RunCMake/Languages/RunCMakeTest.cmake

@@ -4,3 +4,5 @@ run_cmake(NoLangSHARED)
 run_cmake(LINK_LANGUAGE-genex)
 run_cmake(link-libraries-TARGET_FILE-genex)
 run_cmake(link-libraries-TARGET_FILE-genex-ok)
+
+run_cmake(DetermineFail)