GNU patch 2.6.1 fails to build on IRIX

[Stuart Shelton]

On IRIX (and, indeed, any platform without strnlen() or strndup()),
patch 2.6.1 fails with:

cc-1196 cc: WARNING File = gl/lib/strndup.c, Line = 33
  The indicated function is declared implicitly.

    size_t len = strnlen (s, n);
                 ^

cc-1196 cc: WARNING File = gl/lib/xstrndup.c, Line = 36
  The indicated function is declared implicitly.

    char *s = strndup (string, n);
              ^

cc-1140 cc: ERROR File = gl/lib/xstrndup.c, Line = 36
  A value of type "int" cannot be used to initialize an entity of type "char *".

    char *s = strndup (string, n);
              ^

1 error detected in the compilation of "gl/lib/xstrndup.c".
make: *** [gl/lib/xstrndup.o] Error 2

... because 'config.h' says that 'HAVE_DECL_STRNDUP' and
'HAVE_DECL_STRNLEN' should be set to '0' or '1' depending on whether
the function is available, but then the code in these two files checks
to see whether HAVE_DECL_STRNDUP and HAVE_DECL_STRNLEN are defined -
which will always be the case.

patch 2.6.1 also runs into the infamous MIPSpro error:

cc-1999 cc: ERROR File = src/bestmatch.h, Line = 135
  "jumping out of a block containing VLAs" is not currently implemented

1 error detected in the compilation of "src/merge.c".

... but the code (in a header file?) which does this appears to be entirely
superfluous: a for block containing only a 'continue' instruction.  Removing
this allows patch to compile and also pass all of its test-suite.

Patch as follows:

--- ./gl/lib/strndup.c.dist     2010-01-14 16:20:55.486054760 +0000
+++ ./gl/lib/strndup.c  2010-01-14 16:22:49.439646360 +0000
@@ -23,7 +23,7 @@

 #include <stdlib.h>

-#ifndef HAVE_DECL_STRNLEN
+#if HAVE_DECL_STRNLEN != 1
 extern size_t strnlen (const char *, size_t);
 #endif

--- ./gl/lib/xstrndup.c.dist    2010-01-14 16:21:12.090312800 +0000
+++ ./gl/lib/xstrndup.c 2010-01-14 16:22:38.839461080 +0000
@@ -23,7 +23,7 @@
 #include <string.h>
 #include "xalloc.h"

-#ifndef HAVE_DECL_STRNDUP
+#if HAVE_DECL_STRNDUP != 1
 extern char *strndup (const char *, size_t);
 #endif

--- ./src/bestmatch.h.dist      2010-01-14 16:01:40.311100400 +0000
+++ ./src/bestmatch.h   2010-01-14 16:17:17.331202440 +0000
@@ -131,8 +131,9 @@ bestmatch(OFFSET xoff, OFFSET xlim, OFFS
                  x = fd[d - 1] + 1;
                for (y = x - d;
                     x < xlim && y < ylim && EQUAL_IDX (x, y);
-                    x++, y++)
-                 continue;
+                    x++, y++) {
+                 /* continue; */
+               }
                fd[d] = x;
                if (x == xlim && y >= min
                    && x + y - c >= fmid_plus_2_min)