Define/use UNICODE_VERTICAL_LINE

Resolve GCC warning: case value ‘124’ not in enumerated type
  ‘enum unicode_codepoint’

src/xpdev/unicode.c

@@ -411,7 +411,7 @@ char unicode_to_cp437(enum unicode_codepoint codepoint)
 	switch (codepoint) {
 		case UNICODE_ACUTE_ACCENT:                              return '\'';
 
-		case '|':                                               return '|';
+		case UNICODE_VERTICAL_LINE:                             return '|';
 		case UNICODE_BROKEN_BAR:                                return '|';
 		case UNICODE_MACRON:                                    return '~';
 

src/xpdev/unicode_defs.h

@@ -25,6 +25,7 @@
 enum unicode_codepoint {
 	UNICODE_UNDEFINED = 0x0000, // UNICODE_NULL() is defined
 
+	UNICODE_VERTICAL_LINE = 0x007C,
 	UNICODE_NEXT_LINE = 0x0085,
 	UNICODE_REVERSE_LINE_FEED = 0x008D,
 	UNICODE_NO_BREAK_SPACE = 0x00A0,