* aoutx.h, elfcode.h, coff-alpha.c, bout.c, ecoff.c, ecofflink.c,

	* aoutx.h, elfcode.h, coff-alpha.c, bout.c, ecoff.c, ecofflink.c,
	elf32-hppa.c, elf32-mips.c, linker.c, som.c, sunos.c: If malloc(0)
	returns NULL, it is not an error.  It's possible that some of
	these checks are not necessary (because the size can never be
	zero), but putting in the checks is the conservative thing to do
	in light of the fact that some of these malloc calls replaced
	unchecked alloca calls, in which a zero argument would work fine.