move dx8, dx9 etc. to panda-specific Sources.pp files

panda/src/dxgsg7/Sources.pp

@@ -4,6 +4,11 @@
                    dtoolutil:c dtoolbase:c dtool:m
 #define USE_PACKAGES dx
 
+// We link with the DX8 libraries, because they're a superset of DX7
+// anyway, and it means we don't need to have the DX7 SDK available.
+#define WIN_SYS_LIBS \
+   d3d8.lib d3dx8.lib dxerr8.lib
+
 #begin lib_target
 
   #define TARGET dxgsg7

panda/src/dxgsg8/Sources.pp

@@ -1,7 +1,12 @@
 #define BUILD_DIRECTORY $[HAVE_DX]
 
-#define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
-                   dtoolutil:c dtoolbase:c dtool:m
+#define OTHER_LIBS \
+   interrogatedb:c dconfig:c dtoolconfig:m \
+   dtoolutil:c dtoolbase:c dtool:m
+
+#define WIN_SYS_LIBS \
+   d3d8.lib d3dx8.lib dxerr8.lib
+   
 #define USE_PACKAGES dx
 
 #begin lib_target

panda/src/dxgsg9/Sources.pp

@@ -4,6 +4,9 @@
                    dtoolutil:c dtoolbase:c dtool:m
 #define USE_PACKAGES dx
 
+#define WIN_SYS_LIBS \
+   d3d9.lib d3dx9.lib dxerr9.lib
+
 #begin lib_target
   #define TARGET dxgsg9
   #define LOCAL_LIBS \