isalnum: use the Alphabetic derived core property to check that the character is in the alpha class.

src/ctype.c

 {
 	switch (ucd_lookup_category(c))
 	{
+	case UCD_CATEGORY_Lu:
 	case UCD_CATEGORY_Ll:
+	case UCD_CATEGORY_Lt:
 	case UCD_CATEGORY_Lm:
 	case UCD_CATEGORY_Lo:
-	case UCD_CATEGORY_Lt:
-	case UCD_CATEGORY_Lu:
-	case UCD_CATEGORY_Nd:
 	case UCD_CATEGORY_Nl:
+	case UCD_CATEGORY_Nd:
 	case UCD_CATEGORY_No:
 		return 1;
+	case UCD_CATEGORY_Mn:
+	case UCD_CATEGORY_Mc:
+	case UCD_CATEGORY_So:
+		return other_alphabetic_MnMcSo(c);
 	default:
 		return 0;
 	}

tools/printdata.py

 		return 0
 
 def isalnum(data):
-	if data.get('GeneralCategory', 'Cn')[0] in 'LN':
+	if data.get('GeneralCategory', 'Cn')[0] in 'N':
 		return 1
 	else:
-		return 0
+		return data.get('Alphabetic', 0)
 
 def isalpha(data):
 	return data.get('Alphabetic', 0)