configure: add foo_suggest facility
configure: add foo_suggest facility

This is like foo_select, except the selected options being disabled
does not disable foo.

git-svn-id: a4d7c1866f8397a4106e0b57fc4fbf792bbdaaaf@15690 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

prajnashi/ffmpeg,prajnashi/ffmpeg,prajnashi/ffmpeg,prajnashi/ffmpeg