CSS: Move /* #define DEBUG_CSS */ to stylesheet.h.

That's where src/document/css/README says it should be.

src/document/css/apply.c

@@ -27,8 +27,6 @@
 /* XXX: Some strange dependency makes it necessary to this include last. */
 #include "document/html/internal.h"
 
-/* #define DEBUG_CSS */
-
 
 /* TODO: A way to disable CSS completely, PLUS a way to stop various property
  * groups from taking effect. (Ie. way to turn out effect of 'display: none'

src/document/css/parser.c

@@ -21,8 +21,6 @@
 #include "util/memory.h"
 #include "util/string.h"
 
-/* #define DEBUG_CSS */
-
 
 void
 css_parse_properties(struct list_head *props, struct scanner *scanner)

src/document/css/stylesheet.h

@@ -4,6 +4,8 @@
 
 #include "util/lists.h"
 
+/* #define DEBUG_CSS */
+
 /* TODO: We need a memory efficient and fast way to define how properties
  * cascade. What we are interested in is making it fast and easy to find
  * all properties we need.