[PATCH v1 2/2] misc: Replace strcmp with memcmp when it obviously works

[Noah Goldstein]

memcmp is always faster than strcmp. The change in the `a_word`
comparison function is the most important.

All tests pass:
```
$> git clean -xf; ./bootstrap && ./configure && make check
...

977 Tests in 132 Categories Complete ... No Failures :-)

=========================================================================
 Regression PASSED: GNU Make 4.3.90 (x86_64-pc-linux-gnu) built with gcc
=========================================================================
```
---
 src/commands.c | 2 +-
 src/function.c | 9 +++++----
 src/main.c     | 2 +-
 src/read.c     | 2 +-
 4 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/src/commands.c b/src/commands.c
index ee9c5367..00baaca4 100644
--- a/src/commands.c
+++ b/src/commands.c
@@ -119,7 +119,7 @@ set_file_variables (struct file *file)
       for (d = enter_file (strcache_add (".SUFFIXES"))->deps; d ; d = d->next)
         {
           size_t slen = strlen (dep_name (d));
-          if (len > slen && strneq (dep_name (d), name + (len - slen), slen))
+          if (len > slen && (memcmp (dep_name (d), name + (len - slen), slen) 
== 0))
             {
               file->stem = strcache_add_len (name, len - slen);
               break;
diff --git a/src/function.c b/src/function.c
index 38ab9667..92625620 100644
--- a/src/function.c
+++ b/src/function.c
@@ -990,8 +990,9 @@ a_word_hash_cmp (const void *x, const void *y)
   int result = (int) ((struct a_word const *) x)->length - ((struct a_word 
const *) y)->length;
   if (result)
     return result;
-  return_STRING_COMPARE (((struct a_word const *) x)->str,
-                         ((struct a_word const *) y)->str);
+  return_STRING_N_COMPARE (((struct a_word const *) x)->str,
+                           ((struct a_word const *) y)->str,
+                           ((struct a_word const *) y)->length);
 }
 
 struct a_pattern
@@ -1110,7 +1111,7 @@ func_filter_filterout (char *o, char **argv, const char 
*funcname)
       else
         for (wp = words; wp < word_end; ++wp)
           wp->matched |= (wp->length == pp->length
-                          && strneq (pp->str, wp->str, wp->length));
+                          && (memcmp (pp->str, wp->str, wp->length) == 0));
     }
 
   /* Output the words that matched (or didn't, for filter-out).  */
@@ -1245,7 +1246,7 @@ func_sort (char *o, char **argv, const char *funcname 
UNUSED)
         {
           len = strlen (words[i]);
           if (i == wordi - 1 || strlen (words[i + 1]) != len
-              || strcmp (words[i], words[i + 1]))
+              || memcmp (words[i], words[i + 1], len))
             {
               o = variable_buffer_output (o, words[i], len);
               o = variable_buffer_output (o, " ", 1);
diff --git a/src/main.c b/src/main.c
index 66086029..33deb8ff 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1404,7 +1404,7 @@ main (int argc, char **argv, char **envp)
 
         /* If this is MAKE_RESTARTS, check to see if the "already printed
            the enter statement" flag is set.  */
-        if (len == 13 && strneq (envp[i], "MAKE_RESTARTS", 13))
+        if (len == 13 && (memcmp (envp[i], "MAKE_RESTARTS", 13) == 0))
           {
             if (*ep == '-')
               {
diff --git a/src/read.c b/src/read.c
index 12e3cfd0..cb09e7e4 100644
--- a/src/read.c
+++ b/src/read.c
@@ -166,7 +166,7 @@ static char *unescape_char (char *string, int c);
 /* Compare a word, both length and contents.
    P must point to the word to be tested, and WLEN must be the length.
 */
-#define word1eq(s)      (wlen == CSTRLEN (s) && strneq (s, p, CSTRLEN (s)))
+#define word1eq(s)      (wlen == CSTRLEN (s) && (memcmp (s, p, wlen) == 0))
 
 
 /* Read in all the makefiles and return a chain of targets to rebuild.  */
-- 
2.25.1