* config/avr/avr.h (INIT_TARGET_OPTABS): Remove most of it, was
	the same as the default library function names.
	* config/avr/avr.md: Document special characters after '%'.
	(mulqi3, mulhi3, mulsi3): Call libgcc.S functions ourselves,
	knowing which of the call-used registers are really clobbered.
	(divmodqi4, udivmodqi4, divmodhi4, udivmodhi4, divmodsi4, udivmodsi4):
	New.  Both quotient and remainder from one libgcc.S call.
	* config/avr/libgcc.S: Optimize mul/divmod for the new insns above,
	clobber as few registers as possible.
	* config/avr/t-avr (LIB1ASMFUNCS): Adjust for the above changes.

From-SVN: r39155