properly link with pystub

pandatool/src/progbase/Sources.pp

@@ -8,7 +8,12 @@
     pipeline:c event:c panda:m \
     pandabase:c pnmimage:c linmath:c putil:c express:c \
     interrogatedb:c prc:c dconfig:c dtoolconfig:m \
-    dtoolutil:c dtoolbase:c dtool:m
+    dtoolutil:c dtoolbase:c dtool:m \
+    pystub
+
+// We link with pystub so we can include pystub.h here in
+// programBase.cxx, so that every silly little executable in Pandatool
+// doesn't have to include pystub.h.
     
   #define COMBINED_SOURCES $[TARGET]_composite1.cxx