Assembler 'make' errors on Mac OS X

[Richard]

Hi, all.

I'm stumped.

I'm trying to build this package on Mac OS 10.8.3 (command-line tools from Xcode 4.6.3), but getting an error during the make process. I've only found one hit on these forums, but no resolution - I've got the same issue:
http://forum.ipxe.org/showthread.php?tid=4559

$ make
FATAL:/usr/bin/../libexec/as/x86_64/as: I don't understand '-' flag!
[...]
[DEPS] libgcc/__divdi3.c
FATAL:/usr/bin/../libexec/as/x86_64/as: I don't understand '-' flag!
[...]
FATAL:/usr/bin/../libexec/as/x86_64/as: I don't understand '-' flag!
[BUILD] bin/__divdi3.o
In file included from <command-line>:0:
./include/compiler.h:196:1: error: "__weak" redefined
<built-in>: error: this is the location of the previous definition
make: *** [bin/__divdi3.o] Error 1

It seems that an option is being set in the makefiles that the assembler doesn't like. But I've scanned every makefile, tried commenting out every possible ASFLAG assignment, and still I'm getting this error.

Running make -p doesn't reveal a smoking gun. The issue seems to surround the __divdi3.c module, but I'm unclear why the assembler would be called for it (or where).

Caveat: I'm a hack c++/asm/perl coder at best, so out of my element here.

Help!