configure.ac: Add helper function for targets/components
configure.ac: Add helper function for targets/components

Add functions to add and check targets/components.
Not used in this patch.

Signed-off-by: Tobias Droste <6f0b7afb8e169bccf102c27c4328261728913687@gmx.de>
Reviewed-by: Emil Velikov <f20878473f414da183da19ee25c8722cc1d711e4@collabora.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler