r23522: Save us a kilobyte stack space in a hot code path: I can't see a reason

r23522: Save us a kilobyte stack space in a hot code path: I can't see a reason
why check_path_syntax should not be able to run in-line. The destination
pointer either walks side by side with the source pointer or is
decremented. So as far as I can see s>=d is true throughout the whole
routine.

Jeremy, I'm checking this only into 3_0 for now. Please review and ack
or directly merge this to 3_0_26.

Thanks,

Volker
(This used to be commit 34a13c82a3b72d6900614b57c58fbaefeeca8fa7)