[Gc] cc under mac os x

[Grayson, Daniel R.]

I discovered today that libgc doesn't work with /usr/bin/cc under
Mac OS X 10.8.  I usually use gcc, so having it work with cc is not
important to me, but it might be to others.

Most of the tests fail with a segmentation fault.  Gdb shows a deep recursion:

#0  0x0000000100011086 in GC_clear_stack_inner (arg=0x0, limit=0x7fff5fbfa0a0 "") at misc.c:306
#1  0x0000000100011096 in GC_clear_stack_inner (arg=0x0, limit=0x6a8 <Address 0x6a8 out of bounds>) at misc.c:308
#2  0x0000000100011096 in GC_clear_stack_inner (arg=0x0, limit=0x6a8 <Address 0x6a8 out of bounds>) at misc.c:308
#3  0x0000000100011096 in GC_clear_stack_inner (arg=0x0, limit=0x6a8 <Address 0x6a8 out of bounds>) at misc.c:308
#4  0x0000000100011096 in GC_clear_stack_inner (arg=0x0, limit=0x6a8 <Address 0x6a8 out of bounds>) at misc.c:308
#5  0x0000000100011096 in GC_clear_stack_inner (arg=0x0, limit=0x6a8 <Address 0x6a8 out of bounds>) at misc.c:308
#6  0x0000000100011096 in GC_clear_stack_inner (arg=0x0, limit=0x6a8 <Address 0x6a8 out of bounds>) at misc.c:308
#7  0x0000000100011096 in GC_clear_stack_inner (arg=0x0, limit=0x6a8 <Address 0x6a8 out of bounds>) at misc.c:308
#8  0x0000000100011096 in GC_clear_stack_inner (arg=0x0, limit=0x6a8 <Address 0x6a8 out of bounds>) at misc.c:308
#9  0x0000000100011096 in GC_clear_stack_inner (arg=0x0, limit=0x6a8 <Address 0x6a8 out of bounds>) at misc.c:308
#10 0x0000000100011096 in GC_clear_stack_inner (arg=0x0, limit=0x6a8 <Address 0x6a8 out of bounds>) at misc.c:308
#11 0x0000000100011096 in GC_clear_stack_inner (arg=0x0, limit=0x6a8 <Address 0x6a8 out of bounds>) at misc.c:308