cmake: Replace pkg_check_modules with waffle_pkg_config
cmake: Replace pkg_check_modules with waffle_pkg_config

Define a new macro waffle_pkg_config, which replaces each occurence of
pkg_check_modules.

Macro waffle_pkg_config is a smart wrapper around CMake's standard
pkg_check_modules macro.

waffle_pkg_config fixes a fatal flaw of pkg_check_modules.  Unlike
pkg_check_modules, waffle_pkg_config calls pkg-config and checks for the
requested package *each* time the macro is called.

Signed-off-by: Chad Versace <a557f7f75bf28dc19ac99107f5cc7cd6b3fbdb1a@linux.intel.com>

waffle-gl/waffle,chadversary/waffle,maurossi/waffle,maurossi/waffle,dcbaker/waffle,yinquan529/waffle-gl-waffle,yinquan529/waffle-gl-waffle,dcbaker/waffle,fjhenigman/waffle,waffle-gl/waffle,waffle-gl/waffle,maurossi/waffle,evelikov/waffle,evelikov/waffle,chadversary/waffle,evelikov/waffle,waffle-gl/waffle,fjhenigman/waffle,janesma/waffle,dcbaker/waffle,yinquan529/waffle-gl-waffle,janesma/waffle,janesma/waffle,chadversary/waffle,fjhenigman/waffle