Continuation for #3183

Some of the #ifdefs were missed in original PR.
Should be fixed now.

Author: georgthegreat

googletest/include/gtest/gtest-printers.h

@@ -384,7 +384,7 @@ GTEST_IMPL_FORMAT_C_STRING_AS_POINTER_(const char32_t);
 
 GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(char, ::std::string);
 GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(const char, ::std::string);
-#ifdef __cpp_char8_t
+#ifdef __cpp_lib_char8_t
 GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(char8_t, ::std::u8string);
 GTEST_IMPL_FORMAT_C_STRING_AS_STRING_(const char8_t, ::std::u8string);
 #endif
@@ -556,7 +556,7 @@ inline void PrintTo(const ::std::string& s, ::std::ostream* os) {
 }
 
 // Overloads for ::std::u8string
-#ifdef __cpp_char8_t
+#ifdef __cpp_lib_char8_t
 GTEST_API_ void PrintU8StringTo(const ::std::u8string& s, ::std::ostream* os);
 inline void PrintTo(const ::std::u8string& s, ::std::ostream* os) {
   PrintU8StringTo(s, os);