Fold XML attribute whitespace.

tests/core/assets/XML/attribute-whitespace.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE foozle>
+<foozle>Barzle</foozle>
+<부끄러운:barzle>
+	<name foo:bar="   birmese
+	kittens   have
+	fur   ">Indeed!</name>
+</부끄러운:barzle>

tests/core/encoding/xml/test_core_xml.odin

@@ -146,6 +146,20 @@ xml_test_entities_unbox_decode :: proc(t: ^testing.T) {
 	})
 }
 
+@(test)
+xml_test_attribute_whitespace :: proc(t: ^testing.T) {
+	run_test(t, {
+		// Same as above.
+		// Unbox CDATA in data tag.
+		filename  = "XML/attribute-whitespace.xml",
+		options   = {
+			flags = {},
+			expected_doctype = "foozle",
+		},
+		crc32     = 0x8f5fd6c1,
+	})
+}
+
 @(test)
 xml_test_invalid_doctype :: proc(t: ^testing.T) {
 	run_test(t, {