chromium: Check for toolchain being clang as well for deciding on is_clang
chromium: Check for toolchain being clang as well for deciding on is_clang

There are scenarios where someone may setup TOOLCHAIN = "clang" in
local.conf but then not have meta-clang in bblayers.conf which would
actually be ignored if meta-clang is not there, so we also need to make
sure that we have 'toolchain-clang' in OVERRIDES which is only added by
meta-clang and when we want to use clang as default compiler

Signed-off-by: Khem Raj <729d64b6f67515e258459a5f6d20ec88b2caf8df@gmail.com>

schnitzeltony/meta-browser,schnitzeltony/meta-browser,webdino/meta-browser,OSSystems/meta-browser,webdino/meta-browser,webdino/meta-browser,OSSystems/meta-browser,schnitzeltony/meta-browser,webdino/meta-browser,OSSystems/meta-browser,webdino/meta-browser,schnitzeltony/meta-browser,OSSystems/meta-browser