Mechanical conversion to use prefixcmp()

This mechanically converts strncmp() to use prefixcmp(), but only when
the parameters match specific patterns, so that they can be verified
easily.  Leftover from this will be fixed in a separate step, including
idiotic conversions like

    if (!strncmp("foo", arg, 3))

  =>

    if (!(-prefixcmp(arg, "foo")))

This was done by using this script in px.perl

   #!/usr/bin/perl -i.bak -p
   if (/strncmp\(([^,]+), "([^\\"]*)", (\d+)\)/ && (length($2) == $3)) {
           s|strncmp\(([^,]+), "([^\\"]*)", (\d+)\)|prefixcmp($1, "$2")|;
   }
   if (/strncmp\("([^\\"]*)", ([^,]+), (\d+)\)/ && (length($1) == $3)) {
           s|strncmp\("([^\\"]*)", ([^,]+), (\d+)\)|(-prefixcmp($2, "$1"))|;
   }

and running:

   $ git grep -l strncmp -- '*.c' | xargs perl px.perl

Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/help.c b/help.c
index b6674635a2..0893fea025 100644
--- a/help.c
+++ b/help.c
@@ -130,7 +130,7 @@ static void list_commands(const char *exec_path, const char *pattern)
 		struct stat st;
 		int entlen;
 
-		if (strncmp(de->d_name, "git-", 4))
+		if (prefixcmp(de->d_name, "git-"))
 			continue;
 		strcpy(path+dirlen, de->d_name);
 		if (stat(path, &st) || /* stat, not lstat */
@@ -179,7 +179,7 @@ static void show_man_page(const char *git_cmd)
 {
 	const char *page;
 
-	if (!strncmp(git_cmd, "git", 3))
+	if (!prefixcmp(git_cmd, "git"))
 		page = git_cmd;
 	else {
 		int page_len = strlen(git_cmd) + 4;