* c-pragma.h (HANDLE_PRAGMA_WEAK): Define iff ASM_WEAKEN_LABEL and
	ASM_OUTPUT_WEAK_ALIAS are defined.
	* defaults.h (ASM_OUTPUT_WEAK_ALIAS): Define if possible.
	* config/mips/iris6.h (ASM_OUTPUT_WEAK_ALIAS, ASM_WEAKEN_LABEL):
	Moved ...
	* config/mips/iris5.h: ... here.
	(HANDLE_SYSV_PRAGMA): Defined as 1.
	* varasm.c (weak_finish): Use ASM_OUTPUT_WEAK_ALIAS.
	* doc/tm.texi (ASM_OUTPUT_WEAK_ALIAS): Support the undefined weak
	symbol.

Co-Authored-By: Rainer Orth <ro@TechFak.Uni-Bielefeld.DE>

From-SVN: r44072