Handles if a space is encountered while parsing the rule

kati and GNU make may have blank lines in the middle of commands declared in rules.
Add compatibility for this.

Change-Id: Iae03053c0cb901074c26420c0c6ac1c0e00d99de
diff --git a/androidmk/parser/parser.go b/androidmk/parser/parser.go
index fb6be38..8a20bb0 100644
--- a/androidmk/parser/parser.go
+++ b/androidmk/parser/parser.go
@@ -413,6 +413,9 @@
 				p.accept('\t')
 				newLine = false
 				continue loop
+			} else if p.tok == '\n' {
+				p.accept('\n')
+				continue loop
 			} else if p.parseDirective() {
 				newLine = false
 				continue