modpost: rename merror() to error()

The log function names, warn(), merror(), fatal() are inconsistent.

Commit 2a116659 ("kbuild: distinguish between errors and warnings
in modpost") intentionally chose merror() to avoid the conflict with
the library function error(). See man page of error(3).

But, we are already causing the conflict with warn() because it is also
a library function. See man page of warn(3). err() would be a problem
for the same reason.

The common technique to work around name conflicts is to use macros.
For example:

    /* in a header */
    #define error(fmt, ...)  __error(fmt, ##__VA_ARGS__)
    #define warn(fmt, ...)   __warn(fmt, ##__VA_ARGS__)

    /* function definition */
    void __error(const char *fmt, ...)
    {
            <our implementation>
    }

    void __warn(const char *fmt, ...)
    {
            <our implementation>
    }

In this way, we can implement our own warn() and error(), still we can
include <error.h> and <err.h> with no problem.

And, commit 93c95e52 ("modpost: rework and consolidate logging
interface") already did that.

Since the log functions are all macros, we can use error() without
causing "conflicting types" errors.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/mod/modpost.c

@@ -403,8 +403,8 @@ static void sym_update_namespace(const char *symname, const char *namespace)
 	 * actually an assertion.
 	 */
 	if (!s) {
-		merror("Could not update namespace(%s) for symbol %s\n",
-		       namespace, symname);
+		error("Could not update namespace(%s) for symbol %s\n",
+		      namespace, symname);
 		return;
 	}
 
@@ -2226,7 +2226,7 @@ static int check_modname_len(struct module *mod)
 	else
 		mod_name++;
 	if (strlen(mod_name) >= MODULE_NAME_LEN) {
-		merror("module name is too long [%s.ko]\n", mod->name);
+		error("module name is too long [%s.ko]\n", mod->name);
 		return 1;
 	}
 
@@ -2319,8 +2319,8 @@ static int add_versions(struct buffer *b, struct module *mod)
 			continue;
 		}
 		if (strlen(s->name) >= MODULE_NAME_LEN) {
-			merror("too long symbol \"%s\" [%s.ko]\n",
-			       s->name, mod->name);
+			error("too long symbol \"%s\" [%s.ko]\n",
+			      s->name, mod->name);
 			err = 1;
 			break;
 		}

scripts/mod/modpost.h

@@ -202,5 +202,5 @@ enum loglevel {
 void modpost_log(enum loglevel loglevel, const char *fmt, ...);
 
 #define warn(fmt, args...)	modpost_log(LOG_WARN, fmt, ##args)
-#define merror(fmt, args...)	modpost_log(LOG_ERROR, fmt, ##args)
+#define error(fmt, args...)	modpost_log(LOG_ERROR, fmt, ##args)
 #define fatal(fmt, args...)	modpost_log(LOG_FATAL, fmt, ##args)