sb: fix the if logic to handle directives in if statements.

Directives in if statements end at the end of an if. The cannot
change or split across directive boundaries.

Add more trace detail to config.py.

Updates #2661.

source-builder/sb/setbuilder.py

@@ -365,6 +365,11 @@ class buildset:
                         else:
                             deps += b.config.includes()
                         builds += [b]
+                        #
+                        # Dump post build macros.
+                        #
+                        log.trace('_bset: macros post-build')
+                        log.trace(str(macros))
                     else:
                         raise error.general('invalid config type: %s' % (configs[s]))
                 except error.general as gerr: