Tweak the documentation of libiberty's xcrc32 function

libiberty/ChangeLog;

	* crc32.c: In the documentation, don't refer to GDB's
	now-nonexistent crc32 implementation.  In the table-generation
	program embedded within the documentation, change the type of
	the induction variables i and j from int to unsigned int, to
	avoid undefined behavior.

From-SVN: r231983

libiberty/ChangeLog

+2015-12-28  Patrick Palka  <ppalka@gcc.gnu.org>
+
+	* crc32.c: In the documentation, don't refer to GDB's
+	now-nonexistent crc32 implementation.  In the table-generation
+	program embedded within the documentation, change the type of
+	the induction variables i and j from int to unsigned int, to
+	avoid undefined behavior.
+
 2015-12-21  Nick Clifton  <nickc@redhat.com>
 
 	PR 66827

libiberty/crc32.c

@@ -33,15 +33,14 @@
 
 #include "libiberty.h"
 
-/* This table was generated by the following program.  This matches
-   what gdb does.
+/* This table was generated by the following program.
 
    #include <stdio.h>
 
    int
    main ()
    {
-     int i, j;
+     unsigned int i, j;
      unsigned int c;
      int table[256];
 
@@ -146,10 +145,9 @@ starting value is @var{init}; this may be used to compute the CRC of
 data split across multiple buffers by passing the return value of each
 call as the @var{init} parameter of the next.
 
-This is intended to match the CRC used by the @command{gdb} remote
-protocol for the @samp{qCRC} command.  In order to get the same
-results as gdb for a block of data, you must pass the first CRC
-parameter as @code{0xffffffff}.
+This is used by the @command{gdb} remote protocol for the @samp{qCRC}
+command.  In order to get the same results as gdb for a block of data,
+you must pass the first CRC parameter as @code{0xffffffff}.
 
 This CRC can be specified as: