Add 'contrib' tree

contrib/Package.pp

@@ -0,0 +1,60 @@
+//
+// Package.pp
+//
+// This file defines certain configuration variables that are to be
+// written into the various make scripts.  It is processed by ppremake
+// (along with the Sources.pp files in each of the various
+// contribories) to generate build scripts appropriate to each
+// environment.
+//
+// This is the package-specific file, which should be at the top of
+// every source hierarchy.  It generally gets the ball rolling, and is
+// responsible for explicitly including all of the relevent Config.pp
+// files.
+
+// What is the name and version of this source tree?
+#if $[eq $[PACKAGE],]
+  #define PACKAGE contrib
+  #define VERSION 0.80
+#endif
+
+
+// Where should we find the PANDA source contribory?
+#if $[PANDA_SOURCE]
+  #define PANDA_SOURCE $[unixfilename $[PANDA_SOURCE]]
+#elif $[or $[CTPROJS],$[PANDA]]
+  // If we are presently attached, use the environment variable.
+  #define PANDA_SOURCE $[unixfilename $[PANDA]]
+  #if $[eq $[PANDA],]
+    #error You seem to be attached to some trees, but not PANDA!
+  #endif
+#else
+  // Otherwise, if we are not attached, we guess that the source is a
+  // sibling contribory to this source root.
+  #define PANDA_SOURCE $[standardize $[TOPDIR]/../panda]
+#endif
+
+// Where should we install CONTRIB?
+#if $[CONTRIB_INSTALL]
+  #define CONTRIB_INSTALL $[unixfilename $[CONTRIB_INSTALL]]
+#elif $[CTPROJS]
+  #set CONTRIB $[unixfilename $[CONTRIB]]
+  #define CONTRIB_INSTALL $[CONTRIB]/built
+  #if $[eq $[CONTRIB],]
+    #error You seem to be attached to some trees, but not CONTRIB!
+  #endif
+#else
+  #defer CONTRIB_INSTALL $[unixfilename $[INSTALL_DIR]]
+#endif
+
+// Also get the PANDA Package file and everything that includes.
+#if $[not $[isfile $[PANDA_SOURCE]/Package.pp]]
+  #printvar PANDA_SOURCE
+  #error PANDA source contribory not found from contrib!  Are you attached properly?
+#endif
+
+#include $[PANDA_SOURCE]/Package.pp
+
+// Define the inter-tree dependencies.
+#define NEEDS_TREES panda $[NEEDS_TREES]
+#define DEPENDABLE_HEADER_DIRS $[DEPENDABLE_HEADER_DIRS] $[PANDA_INSTALL]/include

contrib/Sources.pp

@@ -0,0 +1,10 @@
+// This is the toplevel directory for a package.
+
+#define DIR_TYPE toplevel
+
+#define REQUIRED_TREES dtool panda
+
+#define EXTRA_DIST \
+    Sources.pp Config.pp Package.pp
+
+#define PYTHON_PACKAGE 1