add USES=jpeg
My plan would be:
- convert the tree to USES=jpeg (for now USES=jpeg uses graphics/jpeg)
- update jpeg-turbo and make jpeg-turbo work on big endian archs
- do an exp-run with USES=jpeg using graphics/jpeg-turbo and the hacks in jpeg-turbo removed (libmap, program-suffix, @comment in plist)
- switch to jpeg-turbo