Correctly handle (?i) in ignores (fixes #1953)

lib/fnmatch/fnmatch.go

@@ -38,14 +38,6 @@ func Convert(pattern string, flags int) (*regexp.Regexp, error) {
 		}
 	}
 
-	// Support case insensitive ignores. We do the loop because we may in some
-	// circumstances end up with multiple insensitivity prefixes
-	// ("(?i)(?i)foo"), which should be accepted.
-	for ignore := strings.TrimPrefix(pattern, "(?i)"); ignore != pattern; ignore = strings.TrimPrefix(pattern, "(?i)") {
-		flags |= CaseFold
-		pattern = ignore
-	}
-
 	if flags&NoEscape != 0 {
 		pattern = strings.Replace(pattern, "\\", "\\\\", -1)
 	} else {