lib/, src/: Use !streq() instead of its pattern

Except for the added (and sorted) includes, and the removal of redundant
parentheses, and one special case, this patch can be approximated with
the following semantic patch:

	$ cat ~/tmp/spatch/strneq.sp;
	@@
	expression a, b;
	@@

	- strcmp(a, b) != 0
	+ !streq(a, b)

	@@
	expression a, b;
	@@

	- 0 != strcmp(a, b)
	+ !streq(a, b)

	$ find contrib/ lib* src/ -type f \
	| xargs spatch --sp-file ~/tmp/spatch/strneq.sp --in-place;

Signed-off-by: Alejandro Colomar <alx@kernel.org>

src/usermod.c

@@ -496,7 +496,7 @@ static void new_pwent (struct passwd *pwent)
 	 * used for this account.
 	 */
 	if (   (!is_shadow_pwd)
-	    || (strcmp (pwent->pw_passwd, SHADOW_PASSWD_STRING) != 0)) {
+	    || !streq(pwent->pw_passwd, SHADOW_PASSWD_STRING)) {
 		pwent->pw_passwd = new_pw_passwd (pwent->pw_passwd);
 	}
 
@@ -1164,7 +1164,7 @@ process_flags(int argc, char **argv)
 				}
 				if (    '\0' != optarg[0]
 				     && '*'  != optarg[0]
-				     && strcmp(optarg, "/sbin/nologin") != 0
+				     && !streq(optarg, "/sbin/nologin")
 				     && (   stat(optarg, &st) != 0
 				         || S_ISDIR(st.st_mode)
 				         || access(optarg, X_OK) != 0)) {