Fix inline assembly for invocation of g++ with -O0

* SAR takes only an immediate or %cl as operands. Thus, %2 needs to be "c" as shift
  can't be an immediate.
* On x86_64 %3 will be stored in a %rXX, thus we need to widen all used registers to 64bit
  or introduce matching suffixes for operands of different sizes. Easiest fix is to change all
  input operands to unsigned long.

Danny van Dyk <kugelfang at gentoo dot org>
--- src/ptlib/common/jidctflt.cxx.orig	2006-03-07 21:50:28.000000000 +0100
+++ src/ptlib/common/jidctflt.cxx	2006-08-29 12:59:04.000000000 +0200
@@ -89,10 +89,10 @@
       "\tsar %2,%1\n"
       "\tsub $-128,%1\n"
       "\tcmovl %5,%1\n"	/* Use the sub to compare to 0 */
-      "\tcmpl %4,%1\n" 
+      "\tcmp %4,%1\n" 
       "\tcmovg %4,%1\n"
       : "=r"(x) 
-      : "0"(x), "Ir"(shift), "ir"(1UL<<(shift-1)), "r" (0xff), "r" (0)
+      : "0"((unsigned long)x), "c"((char)shift), "ir"(1UL<<(shift-1)), "r" (0xffUL), "r" (0UL)
       );
   return x;
 }