* libbfd-in.h: Remove alloca cruft. It was missing some necessary
cruft (like the #pragma alloca for AIX).
In addition to that problem, the C alloca calls xmalloc, which
means checking for being out of memory can't work right. The
following changes remove all uses of alloca from BFD.
* hosts/solaris2.h: Remove alloca cruft.
* som.c: Replace alloca with a fixed size auto array.
* aoutx.h, elfcode.h, nlmcode.h, bout.c, coff-alpha.c, ecoff.c,
ecofflink.c, elf32-hppa.c, elf32-mips.c, linker.c, reloc.c, som.c,
sunos.c: Replace alloca with malloc and appropriate error checking and
freeing.
* linker.c: Replace alloca with obstack_alloc.
* libbfd.h: Rebuilt.