tentative patch to fix warning on Darwin

[Bill Allombert <allomber@math.u-bordeaux.fr>]

Hello PARI-dev,

The buildlogs report the following warning on Darwin:

gcc  -c -O3 -DGCC_INLINE -Wall -fomit-frame-pointer  -no-cpp-precomp -fno-commo
n  -DBOTH_GNUPLOT_AND_X11 -I. -I../src/headers -o init.o ../src/language/init.c
../src/language/init.c: In function `pari_init_stackcheck':
../src/language/init.c:224: warning: comparison is always false due to limited
range of data type

As far as I understand from looking at the code, RLIM_INFINITY is -1 but
we have casted rip.rlim_cur to a ulong so the test will always fail 
(but the alternative will always succeed since (ulong)-1 is bigger than any
ulong but it is per chance).

The following patch should fix this problem (though I have not tested
it).

So if you run OS X, please tell me if this patch fix the warning and
look correct. (Please also check the value of RLIM_INFINITY on this
system).

Cheers,
Bill.

Index: src/language/init.c
===================================================================
RCS file: /home/cvs/pari/src/language/init.c,v
retrieving revision 1.211
diff -u -r1.211 init.c
--- src/language/init.c 10 Dec 2003 16:13:30 -0000      1.211
+++ src/language/init.c 12 Dec 2003 23:53:42 -0000
@@ -221,7 +221,7 @@

   if (getrlimit(RLIMIT_STACK, &rip)) return;
   size = rip.rlim_cur;
-  if (size == RLIM_INFINITY || size > (ulong)stack_base)
+  if (size == (ulong) RLIM_INFINITY || size > (ulong)stack_base)
     PARI_stack_limit = (void*)(((ulong)stack_base) / 16);
   else
     PARI_stack_limit = (void*)((ulong)stack_base - (size/16)*15);