tweaks: correct a parameter type, and correct two empty initializations

This avoids some warnings when compiled with -pedantic:

    ISO C forbids comparison of ‘void *’ with function pointer
    ISO C forbids empty initializer braces

src/global.c

@@ -227,10 +227,10 @@ regmatch_t regmatches[10];
 int hilite_attribute = A_REVERSE;
 	/* The curses attribute we use to highlight something. */
 #ifndef DISABLE_COLOR
-char* specified_color_combo[] = {};
+char* specified_color_combo[] = {'\0'};
 	/* The color combinations as specified in the rcfile. */
 #endif
-int interface_color_pair[] = {};
+int interface_color_pair[] = {0};
 	/* The processed color pairs for the interface elements. */
 
 char *homedir = NULL;

src/rcfile.c

@@ -350,7 +350,7 @@ void parse_syntax(char *ptr)
 /* Check whether the given executable function is "universal" (meaning
  * any horizontal movement or deletion) and thus is present in almost
  * all menus. */
-bool is_universal(void (*func))
+bool is_universal(void (*func)(void))
 {
     if (func == do_left || func == do_right ||
 	func == do_home_void || func == do_end_void ||