Map the negative values of widechar_wcwidth()

Author: creaktive

src/util/widechar_width.h

@@ -21,12 +21,12 @@ namespace {
 /* Special width values */
 enum {
   widechar_nonprint = -1,     // The character is not printable.
-  widechar_combining = -2,    // The character is a zero-width combiner.
-  widechar_ambiguous = -3,    // The character is East-Asian ambiguous width.
-  widechar_private_use = -4,  // The character is for private use.
-  widechar_unassigned = -5,   // The character is unassigned.
-  widechar_widened_in_9 = -6, // Width is 1 in Unicode 8, 2 in Unicode 9+.
-  widechar_non_character = -7 // The character is a noncharacter.
+  widechar_combining = 0,    // The character is a zero-width combiner.
+  widechar_ambiguous = 1,    // The character is East-Asian ambiguous width.
+  widechar_private_use = 1,  // The character is for private use.
+  widechar_unassigned = -1,   // The character is unassigned.
+  widechar_widened_in_9 = 2, // Width is 1 in Unicode 8, 2 in Unicode 9+.
+  widechar_non_character = -1 // The character is a noncharacter.
 };
 
 /* An inclusive range of characters. */