re PR other/54620 (sha1.c has incorrect math if sizeof(size_t) is 8)

	PR other/54620
	* sha1.c (sha1_process_block):  Handle case that size_t is
	a wider-integer-scalar as a 32-bit unsigned integer.

From-SVN: r195604

libiberty/sha1.c

@@ -300,8 +300,7 @@ sha1_process_block (const void *buffer, size_t len, struct sha1_ctx *ctx)
      length of the file up to 2^64 bits.  Here we only compute the
      number of bytes.  Do a double word increment.  */
   ctx->total[0] += len;
-  if (ctx->total[0] < len)
-    ++ctx->total[1];
+  ctx->total[1] += ((len >> 31) >> 1) + (ctx->total[0] < len);
 
 #define rol(x, n) (((x) << (n)) | ((sha1_uint32) (x) >> (32 - (n))))