upgrading to 7.0.3 causes assembly errors

[Evan Laforge]

So I just upgraded to 7, and on compiling I got:

/var/folders/++/+++c0U++6+0++4RjPqRgNE++8+c/-Tmp-/ghc88373_0/ghc88373_1.s:43:0:
   suffix or operands invalid for `push'

/var/folders/++/+++c0U++6+0++4RjPqRgNE++8+c/-Tmp-/ghc88373_0/ghc88373_1.s:47:0:
   suffix or operands invalid for `push'

... etc.

Some digging revealed that it was actually in the compilation of a
*_stub.c file, and the underlying problem is thus:

This is OS X 10.6.  For various reasons, my app is compiled 32 bit,
and I'm explicitly passing '-optc-m32 -opta-m32 -optl-m32' to ghc.
Previously, of course, this wasn't necessary since ghc always produced
32 bit code.  But now there seems to be an issue with flag order.
When ghc wants to compile the stub, it runs:

g++ -x c ./Ui/RulerC_stub.c -o broken.s -m64 -fno-stack-protector
-fno-common -U __PIC__ -D__PIC__ -v -S -Wimplicit -O
-D__GLASGOW_HASKELL__=700 -DTABLES_NEXT_TO_CODE -ggdb -m32 ... rest of
my flags

Then it wants to assemble it:

/Developer/usr/bin/gcc -m32 -I./Ui -Ifltk -I. -c broken.s -o
./Ui/RulerC_stub.o -m64 -fno-stack-protector

So it looks like when compiling, the user flags go last, overriding
the new default -m64.  But when assembling, they go first, and are
overidden.

This seems like an easy fix, I imagine it's just constructing the
cmdline inconsistently.  Is there a way for me to influence how it
constructs the cmdline for gcc for stubs?  I mean, without recompiling
ghc.  I'm supposed to be able to get ghc to compile 32 bit, right?  It
also seems odd to me that it's compiled and assembled separately, but
I suppose there must have been some reason for that.

I guess I should have upgraded sooner to catch this back when there
was a new ghc 7 release every week...