If genpluginprojects is called from fullbuild we set the Python source directory to be the same as fullbuild uses (in stead of using the default sys.prefix). This fixes an issue Mark Day raised that you can't use fullbuild with one Python installation to build another one.
diff --git a/Mac/scripts/genpluginprojects.py b/Mac/scripts/genpluginprojects.py
index ead0c24..0ee6bce 100644
--- a/Mac/scripts/genpluginprojects.py
+++ b/Mac/scripts/genpluginprojects.py
@@ -3,7 +3,8 @@
import os
import string
-PROJECTDIR = os.path.join(sys.prefix, ":Mac:Build")
+PYTHONDIR = sys.prefix
+PROJECTDIR = os.path.join(PYTHONDIR, ":Mac:Build")
MODULEDIRS = [ # Relative to projectdirs
"::Modules:%s",
"::Modules",