[ox] Cleanup string len handling

Remove UTF-8 parsing. It is a rare enough need that it should have a specialized call when needed.
Better to have a more optimal length fetch for typical case.

deps/ox/src/ox/std/CMakeLists.txt

@@ -45,7 +45,7 @@ add_library(
 if(NOT MSVC)
 	target_compile_options(OxStd PRIVATE -Wsign-conversion)
 	target_compile_options(OxStd PRIVATE -Wconversion)
-	if(${OX_OS_LINUX})
+	if(${OX_OS_LINUX} AND NOT CMAKE_CXX_COMPILER_ID MATCHES "Clang")
 		target_compile_options(OxStd PUBLIC -export-dynamic)
 		#target_link_options(OxStd PUBLIC -W1,-E)
 	elseif(${OX_OS_FREEBSD})