* com.c (ffecom_init_0): Define built-in functions for atan2,

	* com.c (ffecom_init_0): Define built-in functions for atan2,
	exp, floor, fmod, log and pow.
	(duplicate_decls): Preserve assembler name when redeclaring a
	built-in.
	* com-rt.def: Implement using the built-in forms of the above
	functions rather than calling the standard C library directly.
	Correct some of the run-time prototype "codes".

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@66714 138bc75d-0d04-0410-961f-82ee72b054a4