Description
Currently emcc issues a warning by default if user passes a command line directive -I/some/absolute/path. This was added to be more user-friendly towards people porting existing build systems which might unconditionally pass include directives to the system include directories that have headers specific to the native host system, which are not meant for Emscripten.
However this default behavior makes emcc a bit unconformant compared to gcc/clang/MSVC and all projects must manually disable the warning if they prefer to pass absolute include directories. Talking on IRC, we decided that we should prefer to be conformant, and default to not showing a warning here. Instead, for developers that are starting up a port project of a new codebase, they can pass `-Wwarn-absolute-paths' to enable the warning if needed. We should add a mention of this aid in a porting guide somewhere in the docs.