Merge from gnulib

This merges some getopt fixes from Zack Weinberg, and affects only
non-GNUish platforms.  It incorporates:
2017-04-06 getopt-gnu: omit some duplicate code
2017-04-06 getopt-posix: use angle-bracket include
2017-04-06 getopt: annotate files with relationship to glibc
2017-04-06 getopt: split up getopt.in.h and eliminate __need_getopt
2017-04-06 getopt: better handling of ambiguous options
2017-04-06 getopt: refactor long-option handling
2017-04-06 getopt: tidy up _getopt_initialize a bit
2017-04-06 getopt: merge from glibc: repetition reduction
2017-04-06 getopt: clean up error reporting
2017-04-06 getopt: fix fencepost error in ambiguous-W-option handling
2017-04-06 getopt: clean up getopt.c and getopt1.c file headers
2017-04-06 getopt: harmonize comments with glibc
2017-04-06 getopt: remove USE_NONOPTION_FLAGS
2017-04-06 getopt: tabify, in preparation for merge with glibc
2017-04-06 md5, sha1, sha256, sha512: Add comments re correctness
* build-aux/config.sub, doc/misc/texinfo.tex, lib/getopt.c:
* lib/getopt.in.h, lib/getopt1.c, lib/getopt_int.h, lib/md5.c:
* lib/md5.h, lib/sha1.c, lib/sha1.h, lib/sha256.c, lib/sha256.h:
* lib/sha512.c, lib/sha512.h, lib/unistd.in.h, m4/getopt.m4:
Copy from gnulib.
* lib/getopt_cdefs.in.h, lib/getopt_core.h, lib/getopt_ext.h:
* lib/getopt_pfx_core.h, lib/getopt_pfx_ext.h:
New files, taken from gnulib.
* lib/gnulib.mk.in, m4/gnulib-comp.m4:
Regenerate.

1 files changed, 4 insertions, 1 deletions

diff --git a/lib/md5.c b/lib/md5.c
index e82b0514a0a..dcbba45ddff 100644
--- a/lib/md5.c
+++ b/lib/md5.c
@@ -246,7 +246,8 @@ md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx)
           md5_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
 
           ctx->buflen &= 63;
-          /* The regions in the following copy operation cannot overlap.  */
+          /* The regions in the following copy operation cannot overlap,
+             because ctx->buflen < 64 ≤ (left_over + add) & ~63.  */
           memcpy (ctx->buffer,
                   &((char *) ctx->buffer)[(left_over + add) & ~63],
                   ctx->buflen);
@@ -288,6 +289,8 @@ md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx)
         {
           md5_process_block (ctx->buffer, 64, ctx);
           left_over -= 64;
+          /* The regions in the following copy operation cannot overlap,
+             because left_over ≤ 64.  */
           memcpy (ctx->buffer, &ctx->buffer[16], left_over);
         }
       ctx->buflen = left_over;