fmt_compile.c: Alter FINDCOMP(): the caller must supply the semicolon.

fmt_compile.c: Alter FINDCOMP(): the caller must supply the semicolon.

The macro expands to a for-loop, including the semicolon body.  The
caller typically supplies their own semicolon.  This results in two on
one line that looks odd.  Alter the macro to have the for-loop inside a
do-while loop that doesn't have a semicolon, ensuring the caller must
supply it.