re PR target/49313 (Inefficient libgcc implementations for avr)

	PR target/49313
	* config/avr/t-avr (LIB2FUNCS_EXCLUDE): Add _moddi3, _umoddi3.
	(LIB1ASMFUNCS): Add _divdi3, _udivdi3, _udivmod64, _negdi2.
	* config/avr/lib1funcs.S (wmov): New assembler macro.
	(__umoddi3, __udivdi3, __udivdi3_umoddi3): New functions.
	(__moddi3, __divdi3, __divdi3_moddi3): New functions.
	(__udivmod64): New function.
	(__negdi2): New function.

From-SVN: r181551