Prompted by PRs gas/11516 and gas/11517, I tried to enable explicit relocations
for Alpha ECOFF, too, to see if I get further along with gas and gcc on Tru64
UNIX with this combination.  At least the trivial change of defining RELOC_OP_P
in config/tc-alpha.h is not enough: trying to assemble the jsr.s testcase from
PR gas/11516 fails with a SEGV:

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 1 (LWP 1)]
0x08091e3d in assemble_insn (opcode=0x80f2200, tok=0x80476d0, ntok=3,
insn=0x8047660, reloc=BFD_RELOC_ALPHA_ELF_LITERAL) at
/vol/gnu/src/binutils/binutils-2.20/gas/config/tc-alpha.c:2130
(gdb) p reloc_howto
$1 = (const struct reloc_howto_struct *) 0x0
(gdb) p reloc
$2 = BFD_RELOC_ALPHA_ELF_LITERAL

Obviously RELOC_OP_P also means OBJ_ELF in a couple of places, so this maze
needs to be untangled to have a chance to make gas work this way.