Tidy code to get rid of compiler warnings.

ChangeLog

@@ -2,7 +2,7 @@ Change Log for PCRE2
 --------------------
 
 
-Version 10.22 29-June-2016
+Version 10.22 29-July-2016
 --------------------------
 
 1. Applied Jason Hood's patches to RunTest.bat and testdata/wintestoutput3
@@ -174,6 +174,8 @@ large stack size when testing with clang.
 
 45. Fix unaligned accesses on x86. Patch by Marc Mutz.
 
+46. Fix some more clang compiler warnings.
+
 
 Version 10.21 12-January-2016
 -----------------------------

src/pcre2_printint.c

@@ -214,7 +214,7 @@ while (*ptr != '\0')
 static void
 print_custring_bylen(FILE *f, PCRE2_SPTR ptr, PCRE2_UCHAR len)
 {
-while (len-- > 0)
+for (; len > 0; len--)
   {
   register uint32_t c = *ptr++;
   if (PRINTABLE(c)) fprintf(f, "%c", c); else fprintf(f, "\\x{%x}", c);

src/pcre2test.c

@@ -4663,7 +4663,7 @@ else if ((pat_patctl.control & CTL_EXPAND) != 0)
       pt = pbuffer8 + pt_offset;
       }
 
-    while (count-- > 0)
+    for (; count > 0; count--)
       {
       memcpy(pt, pc, length);
       pt += length;