section breakage on ppc64 (aka __devinitconst is broken by design)

[Al Viro <viro@ZenIV.linux.org.uk>]

; cat >a.c <<'EOF'
const char foo[] __attribute__ ((__section__(".blah"))) = "";
const char * const bar __attribute__((__section__(".blah"))) = "";
EOF
; gcc -m32 -S a.c
; gcc -m64 -S a.c
a.c:2: error: bar causes a section type conflict
;

That's 4.1.2 on ppc.  What happens is that the second declaration
wants to make .blah writable.  We actually trigger that in ppc64
builds on drivers/net/natsemi.c.

Note that on ppc64 without explicit sections you have the second one land in
.data.rel.ro.local, which is "aw",progbits.

The reason why it didn't visibly bite us before is that usually __devinit...
just expanded to nothing (unless you disable HOTPLUG, which requires
EMBEDDED, which wasn't apparently common enough for ppc64 builds).

Suggestions?