[PATCH] H8/300, libgcc: PR target/114222 For HImode call internal ffs() implementation instead of an external one

When INT_TYPE_SIZE < BITS_PER_WORD gcc emits a call to an external ffs()
implementation instead of a call to "__builtin_ffs()" – see function
init_optabs() in <SRCROOT>/gcc/optabs-libfuncs.cc. External ffs()
(which is usually the one from newlib) in turn calls __builtin_ffs()
what causes infinite recursion and stack overflow. This patch overrides
default gcc bahaviour for H8/300H (and newer) and provides a generic
ffs() implementation for HImode.

	PR target/114222
gcc/ChangeLog:

	* config/h8300/h8300.cc (h8300_init_libfuncs): For HImode override
	calls to external ffs() (from newlib) with calls to __ffshi2() from
	libgcc. The implementation of ffs() in newlib calls __builtin_ffs()
	what causes infinite recursion and finally a stack overflow.

libgcc/ChangeLog:

	* config/h8300/t-h8300: Add __ffshi2().
	* config/h8300/ffshi2.c: New file.