diff --git a/direct/src/directd/Sources.pp b/direct/src/directd/Sources.pp
index 5db4429a25..9fd79b66d8 100644
--- a/direct/src/directd/Sources.pp
+++ b/direct/src/directd/Sources.pp
@@ -1,9 +1,7 @@
 
 // This package presently only builds on Windows.
-#define DIRECTORY_IF_WINDOWS yes
-
 // We also require the network layer (queuedConnectionManager, etc.)
-#define DIRECTORY_IF_NET yes
+#define BUILD_DIRECTORY $[and $[WINDOWS_PLATFORM],$[HAVE_NET]]
 
 #define LOCAL_LIBS \
     directbase
diff --git a/direct/src/directdServer/Sources.pp b/direct/src/directdServer/Sources.pp
index bf2fd216ab..388cc1e51d 100644
--- a/direct/src/directdServer/Sources.pp
+++ b/direct/src/directdServer/Sources.pp
@@ -1,9 +1,7 @@
 
 // This package presently only builds on Windows.
-#define DIRECTORY_IF_WINDOWS yes
-
 // We also require the network layer (queuedConnectionManager, etc.)
-#define DIRECTORY_IF_NET yes
+#define BUILD_DIRECTORY $[and $[WINDOWS_PLATFORM],$[HAVE_NET]]
 
 //#define LOCAL_LIBS \
 //    directbase
diff --git a/dtool/pptempl/Global.pp b/dtool/pptempl/Global.pp
index cde9b4a72e..56e8161fef 100644
--- a/dtool/pptempl/Global.pp
+++ b/dtool/pptempl/Global.pp
@@ -241,72 +241,27 @@
   #define chromium_libs $[CHROMIUM_LIBS]
 #endif
 
+// We define these two variables true here in the global scope; a
+// particular Sources.pp file can redefine these to be false to
+// prevent a particular directory or target from being built in
+// certain circumstances.
+#define BUILD_DIRECTORY 1
+#define BUILD_TARGET 1
+
 // This variable, when evaluated in the scope of a particular directory,
 // will indicate true (i.e. nonempty) when the directory is truly built,
 // or false (empty) when the directory is not to be built.
-#defer build_directory \
- $[and \
-     $[or $[not $[DIRECTORY_IF_WINDOWS]],$[WINDOWS_PLATFORM]], \
-     $[or $[not $[DIRECTORY_IF_UNIX]],$[UNIX_PLATFORM]], \
-     $[or $[not $[DIRECTORY_IF_PYTHON]],$[HAVE_PYTHON]], \
-     $[or $[not $[DIRECTORY_IF_NSPR]],$[HAVE_NSPR]], \
-     $[or $[not $[DIRECTORY_IF_CRYPTO]],$[HAVE_CRYPTO]], \
-     $[or $[not $[DIRECTORY_IF_ZLIB]],$[HAVE_ZLIB]], \
-     $[or $[not $[DIRECTORY_IF_SOXST]],$[HAVE_SOXST]], \
-     $[or $[not $[DIRECTORY_IF_GL]],$[HAVE_GL]], \
-     $[or $[not $[DIRECTORY_IF_CHROMIUM]],$[HAVE_CHROMIUM]], \
-     $[or $[not $[DIRECTORY_IF_DX]],$[HAVE_DX]], \
-     $[or $[not $[DIRECTORY_IF_GLX]],$[HAVE_GLX]], \
-     $[or $[not $[DIRECTORY_IF_GLUT]],$[HAVE_GLUT]], \
-     $[or $[not $[DIRECTORY_IF_WGL]],$[HAVE_WGL]], \
-     $[or $[not $[DIRECTORY_IF_RIB]],$[HAVE_RIB]], \
-     $[or $[not $[DIRECTORY_IF_PS2]],$[HAVE_PS2]], \
-     $[or $[not $[DIRECTORY_IF_SGIGL]],$[HAVE_SGIGL]], \
-     $[or $[not $[DIRECTORY_IF_JPEG]],$[HAVE_JPEG]], \
-     $[or $[not $[DIRECTORY_IF_JPEG2000]],$[HAVE_JPEG2000]], \
-     $[or $[not $[DIRECTORY_IF_TIFF]],$[HAVE_TIFF]], \
-     $[or $[not $[DIRECTORY_IF_FFTW]],$[HAVE_FFTW]], \
-     $[or $[not $[DIRECTORY_IF_VRPN]],$[HAVE_VRPN]], \
-     $[or $[not $[DIRECTORY_IF_GTKMM]],$[HAVE_GTKMM]], \
-     $[or $[not $[DIRECTORY_IF_MAYA]],$[HAVE_MAYA]], \
-     $[or $[not $[DIRECTORY_IF_IPC]],$[HAVE_IPC]], \
-     $[or $[not $[DIRECTORY_IF_NET]],$[HAVE_NET]], \
-     $[or $[not $[DIRECTORY_IF_AUDIO]],$[HAVE_AUDIO]], \
-     $[or $[not $[DIRECTORY_IF_INTERROGATE]],$[HAVE_INTERROGATE]], \
-      1 ]
+#defer build_directory $[BUILD_DIRECTORY]
+// It maps to a direct evaluation of the user-set variable,
+// BUILD_DIRECTORY, for historical reasons.  This also allows us to
+// reserve the right to extend this variable to test other conditions
+// as well, should the need arise.
 
 // This variable, when evaluated in the scope of a particular target,
 // will indicated true when the target should be built, or false when
 // the target is not to be built.
-#defer build_target \
- $[and \
-     $[or $[not $[TARGET_IF_WINDOWS]],$[WINDOWS_PLATFORM]], \
-     $[or $[not $[TARGET_IF_UNIX]],$[UNIX_PLATFORM]], \
-     $[or $[not $[TARGET_IF_PYTHON]],$[HAVE_PYTHON]], \
-     $[or $[not $[TARGET_IF_NSPR]],$[HAVE_NSPR]], \
-     $[or $[not $[TARGET_IF_CRYPTO]],$[HAVE_CRYPTO]], \
-     $[or $[not $[TARGET_IF_ZLIB]],$[HAVE_ZLIB]], \
-     $[or $[not $[TARGET_IF_SOXST]],$[HAVE_SOXST]], \
-     $[or $[not $[TARGET_IF_GL]],$[HAVE_GL]], \
-     $[or $[not $[TARGET_IF_CHROMIUM]],$[HAVE_CHROMIUM]], \
-     $[or $[not $[TARGET_IF_DX]],$[HAVE_DX]], \
-     $[or $[not $[TARGET_IF_GLX]],$[HAVE_GLX]], \
-     $[or $[not $[TARGET_IF_GLUT]],$[HAVE_GLUT]], \
-     $[or $[not $[TARGET_IF_WGL]],$[HAVE_WGL]], \
-     $[or $[not $[TARGET_IF_RIB]],$[HAVE_RIB]], \
-     $[or $[not $[TARGET_IF_PS2]],$[HAVE_PS2]], \
-     $[or $[not $[TARGET_IF_SGIGL]],$[HAVE_SGIGL]], \
-     $[or $[not $[TARGET_IF_JPEG]],$[HAVE_JPEG]], \
-     $[or $[not $[TARGET_IF_JPEG2000]],$[HAVE_JPEG2000]], \
-     $[or $[not $[TARGET_IF_TIFF]],$[HAVE_TIFF]], \
-     $[or $[not $[TARGET_IF_FFTW]],$[HAVE_FFTW]], \
-     $[or $[not $[TARGET_IF_VRPN]],$[HAVE_VRPN]], \
-     $[or $[not $[TARGET_IF_GTKMM]],$[HAVE_GTKMM]], \
-     $[or $[not $[TARGET_IF_MAYA]],$[HAVE_MAYA]], \
-     $[or $[not $[TARGET_IF_IPC]],$[HAVE_IPC]], \
-     $[or $[not $[TARGET_IF_NET]],$[HAVE_NET]], \
-     $[or $[not $[TARGET_IF_RAD_MSS]],$[HAVE_RAD_MSS]], \
-      1 ]
+#defer build_target $[BUILD_TARGET]
+
 
 // This takes advantage of the above two variables to get the actual
 // list of local libraries we are to link with, eliminating those that
diff --git a/dtool/src/cppparser/Sources.pp b/dtool/src/cppparser/Sources.pp
index 7cad7041b1..e23caac21a 100644
--- a/dtool/src/cppparser/Sources.pp
+++ b/dtool/src/cppparser/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_INTERROGATE yes
+#define BUILD_DIRECTORY $[HAVE_INTERROGATE]
 
 #define LOCAL_LIBS dtoolutil dtoolbase
 #define YACC_PREFIX cppyy
@@ -40,17 +40,4 @@
      cppTypeParser.cxx cppTypeProxy.cxx cppTypedef.cxx  \
      cppUsing.cxx cppVisibility.cxx indent.cxx 
 
-// These are temporary; they need not be installed in the future.  These are
-// necessary only when using template stopgap.
-  #define INSTALL_HEADERS \
-    cppDeclaration.h cppExtensionType.h cppIdentifier.h cppInstance.h \
-    cppManifest.h cppPreprocessor.h cppScope.h cppToken.h cppType.h \
-    cppVisibility.h cppBisonDefs.h cppParser.h cppInstanceIdentifier.h \
-    cppFunctionType.h cppSimpleType.h cppParameterList.h cppTypedef.h \
-    cppTypeDeclaration.h \
-    cppPointerType.h cppReferenceType.h cppConstType.h cppArrayType.h \
-    cppEnumType.h cppStructType.h cppFile.h cppTemplateParameterList.h \
-    cppFunctionGroup.h cppNameComponent.h cppTypeProxy.h cppTBDType.h \
-    cppExpressionParser.h cppExpression.h cppGlobals.h cppCommentBlock.h
-
 #end static_lib_target
diff --git a/dtool/src/interrogate/Sources.pp b/dtool/src/interrogate/Sources.pp
index 2c810bac06..42b487efe5 100644
--- a/dtool/src/interrogate/Sources.pp
+++ b/dtool/src/interrogate/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_INTERROGATE yes
+#define BUILD_DIRECTORY $[HAVE_INTERROGATE]
 
 #define LOCAL_LIBS cppParser pystub interrogatedb dconfig dtoolutil dtoolbase
 
diff --git a/panda/metalibs/pandacr/Sources.pp b/panda/metalibs/pandacr/Sources.pp
index 698c87bc04..3e4fd20ce4 100644
--- a/panda/metalibs/pandacr/Sources.pp
+++ b/panda/metalibs/pandacr/Sources.pp
@@ -6,7 +6,7 @@
 
 #define DIR_TYPE metalib
 #define BUILDING_DLL BUILDING_PANDACR
-#define DIRECTORY_IF_CHROMIUM yes
+#define BUILD_DIRECTORY $[HAVE_CHROMIUM]
 
 //#define USE_CHROMIUM yes
 
diff --git a/panda/metalibs/pandadx/Sources.pp b/panda/metalibs/pandadx/Sources.pp
index 7dc2dfd153..484da72f6e 100644
--- a/panda/metalibs/pandadx/Sources.pp
+++ b/panda/metalibs/pandadx/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_DX yes
+#define BUILD_DIRECTORY $[HAVE_DX]
 
 // DIR_TYPE "metalib" indicates we are building a shared library that
 // consists mostly of references to other shared libraries.  Under
diff --git a/panda/metalibs/pandadx8/Sources.pp b/panda/metalibs/pandadx8/Sources.pp
index 443cd0dd27..6078a9dbd2 100644
--- a/panda/metalibs/pandadx8/Sources.pp
+++ b/panda/metalibs/pandadx8/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_DX yes
+#define BUILD_DIRECTORY $[HAVE_DX]
 
 // DIR_TYPE "metalib" indicates we are building a shared library that
 // consists mostly of references to other shared libraries.  Under
diff --git a/panda/metalibs/pandagl/Sources.pp b/panda/metalibs/pandagl/Sources.pp
index f219207c2d..9a807c6ec9 100644
--- a/panda/metalibs/pandagl/Sources.pp
+++ b/panda/metalibs/pandagl/Sources.pp
@@ -6,7 +6,7 @@
 
 #define DIR_TYPE metalib
 #define BUILDING_DLL BUILDING_PANDAGL
-#define DIRECTORY_IF_GL yes
+#define BUILD_DIRECTORY $[HAVE_GL]
 
 #if $[eq $[LINK_IN_GL],]
   // We don't have any components if we're linking the GL library
diff --git a/panda/metalibs/pandarib/Sources.pp b/panda/metalibs/pandarib/Sources.pp
index c3f140cc89..1112cceb31 100644
--- a/panda/metalibs/pandarib/Sources.pp
+++ b/panda/metalibs/pandarib/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_RIB yes
+#define BUILD_DIRECTORY $[HAVE_RIB]
 
 // DIR_TYPE "metalib" indicates we are building a shared library that
 // consists mostly of references to other shared libraries.  Under
diff --git a/panda/src/audio/Sources.pp b/panda/src/audio/Sources.pp
index 8de589b787..c83ebad5c2 100644
--- a/panda/src/audio/Sources.pp
+++ b/panda/src/audio/Sources.pp
@@ -1,5 +1,5 @@
 #define OTHER_LIBS dtoolconfig dtool
-#define DIRECTORY_IF_AUDIO yes
+#define BUILD_DIRECTORY $[HAVE_AUDIO]
 
 #begin lib_target
   #define TARGET audio
diff --git a/panda/src/audiotraits/Sources.pp b/panda/src/audiotraits/Sources.pp
index b1c8c4907f..49905c7530 100644
--- a/panda/src/audiotraits/Sources.pp
+++ b/panda/src/audiotraits/Sources.pp
@@ -1,9 +1,9 @@
 #define OTHER_LIBS dtoolconfig dtool
-#define DIRECTORY_IF_AUDIO yes
+#define BUILD_DIRECTORY $[HAVE_AUDIO]
 
 #begin lib_target
   #define TARGET miles_audio
-  #define TARGET_IF_RAD_MSS yes
+  #define BUILD_TARGET $[HAVE_RAD_MSS]
   #define USE_RAD_MSS yes
   #define BUILDING_DLL BUILDING_MILES_AUDIO
   #define LOCAL_LIBS audio
diff --git a/panda/src/crgsg/Sources.pp b/panda/src/crgsg/Sources.pp
index 551899b0ca..2b3fd52d9f 100644
--- a/panda/src/crgsg/Sources.pp
+++ b/panda/src/crgsg/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_CHROMIUM yes
+#define BUILD_DIRECTORY $[HAVE_CHROMIUM]
 
 #define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
                    dtoolutil:c dtoolbase:c dtool:m
diff --git a/panda/src/downloadertools/Sources.pp b/panda/src/downloadertools/Sources.pp
index 9974745b3f..6878ac0073 100644
--- a/panda/src/downloadertools/Sources.pp
+++ b/panda/src/downloadertools/Sources.pp
@@ -2,11 +2,11 @@
                    dtoolutil:c dtoolbase:c dtool:m pystub
 #define LOCAL_LIBS downloader express event ipc
 #define USE_IPC yes
-#define DIRECTORY_IF_IPC yes
+#define BUILD_DIRECTORY $[HAVE_IPC]
 
 #begin bin_target
   #define TARGET apply_patch
-  #define TARGET_IF_CRYPTO yes
+  #define BUILD_TARGET $[HAVE_CRYPTO]
 
   #define SOURCES \
     apply_patch.cxx
@@ -17,7 +17,7 @@
 
 #begin bin_target
   #define TARGET build_patch
-  #define TARGET_IF_CRYPTO yes
+  #define BUILD_TARGET $[HAVE_CRYPTO]
 
   #define SOURCES \
     build_patch.cxx
@@ -26,7 +26,7 @@
 
 #begin bin_target
   #define TARGET check_adler
-  #define TARGET_IF_ZLIB yes
+  #define BUILD_TARGET $[HAVE_ZLIB]
   #define USE_ZLIB yes
 
   #define SOURCES \
@@ -36,7 +36,7 @@
 
 #begin bin_target
   #define TARGET check_crc
-  #define TARGET_IF_ZLIB yes
+  #define BUILD_TARGET $[HAVE_ZLIB]
   #define USE_ZLIB yes
 
   #define SOURCES \
@@ -46,7 +46,7 @@
 
 #begin bin_target
   #define TARGET check_md5
-  #define TARGET_IF_CRYPTO yes
+  #define BUILD_TARGET $[HAVE_CRYPTO]
   #define USE_CRYPTO yes
 
   #define SOURCES \
@@ -64,7 +64,7 @@
 
 #begin bin_target
   #define TARGET pcompress
-  #define TARGET_IF_ZLIB yes
+  #define BUILD_TARGET $[HAVE_ZLIB]
   #define USE_ZLIB yes
 
   #define SOURCES \
@@ -74,7 +74,7 @@
 
 #begin bin_target
   #define TARGET pdecompress
-  #define TARGET_IF_ZLIB yes
+  #define BUILD_TARGET $[HAVE_ZLIB]
   #define USE_ZLIB yes
 
   #define SOURCES \
@@ -84,7 +84,7 @@
 
 #begin bin_target
   #define TARGET test_downloader
-  #define TARGET_IF_ZLIB yes
+  #define BUILD_TARGET $[HAVE_ZLIB]
   #define USE_ZLIB yes
 
   #define SOURCES \
diff --git a/panda/src/dxgsg/Sources.pp b/panda/src/dxgsg/Sources.pp
index 433a38283c..b4a1102655 100644
--- a/panda/src/dxgsg/Sources.pp
+++ b/panda/src/dxgsg/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_DX yes
+#define BUILD_DIRECTORY $[HAVE_DX]
 
 #define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
                    dtoolutil:c dtoolbase:c dtool:m
diff --git a/panda/src/dxgsg8/Sources.pp b/panda/src/dxgsg8/Sources.pp
index 7221356812..587cccc8e9 100644
--- a/panda/src/dxgsg8/Sources.pp
+++ b/panda/src/dxgsg8/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_DX yes
+#define BUILD_DIRECTORY $[HAVE_DX]
 
 #define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
                    dtoolutil:c dtoolbase:c dtool:m
diff --git a/panda/src/glgsg/Sources.pp b/panda/src/glgsg/Sources.pp
index c5c133690c..c17c871be1 100644
--- a/panda/src/glgsg/Sources.pp
+++ b/panda/src/glgsg/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_GL yes
+#define BUILD_DIRECTORY $[HAVE_GL]
 
 #define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
                    dtoolutil:c dtoolbase:c dtool:m
diff --git a/panda/src/glutdisplay/Sources.pp b/panda/src/glutdisplay/Sources.pp
index 03f98fa8cb..b5f1da9dfb 100644
--- a/panda/src/glutdisplay/Sources.pp
+++ b/panda/src/glutdisplay/Sources.pp
@@ -1,5 +1,4 @@
-#define DIRECTORY_IF_GL yes
-#define DIRECTORY_IF_GLUT yes
+#define BUILD_DIRECTORY $[HAVE_GLUT]
 
 #define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
                    dtoolutil:c dtoolbase:c dtool:m
diff --git a/panda/src/glxdisplay/Sources.pp b/panda/src/glxdisplay/Sources.pp
index 5a80f5217c..a08f7707d0 100644
--- a/panda/src/glxdisplay/Sources.pp
+++ b/panda/src/glxdisplay/Sources.pp
@@ -1,5 +1,4 @@
-#define DIRECTORY_IF_GL yes
-#define DIRECTORY_IF_GLX yes
+#define BUILD_DIRECTORY $[HAVE_GLX]
 
 #define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
                    dtoolutil:c dtoolbase:c dtool:m
diff --git a/panda/src/ipc/Sources.pp b/panda/src/ipc/Sources.pp
index cd5d815bea..bd404c7c1b 100644
--- a/panda/src/ipc/Sources.pp
+++ b/panda/src/ipc/Sources.pp
@@ -3,7 +3,7 @@
                    dtoolutil:c dtoolbase:c dtool:m
 #define USE_NSPR yes
 #define USE_IPC yes
-#define DIRECTORY_IF_IPC yes
+#define BUILD_DIRECTORY $[HAVE_IPC]
 
 #begin lib_target
   #define TARGET ipc
diff --git a/panda/src/net/Sources.pp b/panda/src/net/Sources.pp
index 4f0819d826..9ac79fb91d 100644
--- a/panda/src/net/Sources.pp
+++ b/panda/src/net/Sources.pp
@@ -1,7 +1,6 @@
 #define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
                    dtoolutil:c dtoolbase:c dtool:m
-#define DIRECTORY_IF_NET yes
-#define DIRECTORY_IF_NSPR yes
+#define BUILD_DIRECTORY $[and $[HAVE_NET],$[HAVE_NSPR]]
 #define USE_NET yes
 #define USE_NSPR yes
 
diff --git a/panda/src/ps2display/Sources.pp b/panda/src/ps2display/Sources.pp
index f0d16fab08..55f0b845a4 100644
--- a/panda/src/ps2display/Sources.pp
+++ b/panda/src/ps2display/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_PS2 yes
+#define BUILD_DIRECTORY $[HAVE_PS2]
 
 #define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
                    dtoolutil:c dtoolbase:c dtool:m
diff --git a/panda/src/ps2gsg/Sources.pp b/panda/src/ps2gsg/Sources.pp
index 93a0bdf2c1..45901ed825 100644
--- a/panda/src/ps2gsg/Sources.pp
+++ b/panda/src/ps2gsg/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_PS2 yes
+#define BUILD_DIRECTORY $[HAVE_PS2]
 
 #define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
                    dtoolutil:c dtoolbase:c dtool:m
diff --git a/panda/src/ribdisplay/Sources.pp b/panda/src/ribdisplay/Sources.pp
index 289f82dadb..a010b83366 100644
--- a/panda/src/ribdisplay/Sources.pp
+++ b/panda/src/ribdisplay/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_RIB yes
+#define BUILD_DIRECTORY $[HAVE_RIB]
 
 #define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
                    dtoolutil:c dtoolbase:c dtool:m
diff --git a/panda/src/ribgsg/Sources.pp b/panda/src/ribgsg/Sources.pp
index 5789722ef7..6f66246edf 100644
--- a/panda/src/ribgsg/Sources.pp
+++ b/panda/src/ribgsg/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_RIB yes
+#define BUILD_DIRECTORY $[HAVE_RIB]
 
 #define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
                    dtoolutil:c dtoolbase:c dtool:m
diff --git a/panda/src/sgidisplay/Sources.pp b/panda/src/sgidisplay/Sources.pp
index 946cd4cb9b..2a871ae2fd 100644
--- a/panda/src/sgidisplay/Sources.pp
+++ b/panda/src/sgidisplay/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_SGIGL yes
+#define BUILD_DIRECTORY $[HAVE_SGIGL]
 
 #define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
                    dtoolutil:c dtoolbase:c dtool:m
diff --git a/panda/src/sgiglutdisplay/Sources.pp b/panda/src/sgiglutdisplay/Sources.pp
index 43e4abfbb7..ca9fb1df81 100644
--- a/panda/src/sgiglutdisplay/Sources.pp
+++ b/panda/src/sgiglutdisplay/Sources.pp
@@ -1,5 +1,4 @@
-#define DIRECTORY_IF_SGIGL yes
-#define DIRECTORY_IF_GLUT yes
+#define BUILD_DIRECTORY $[and $[HAVE_SGIGL],$[HAVE_GLUT]]
 
 #define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
                    dtoolutil:c dtoolbase:c dtool:m
diff --git a/panda/src/sgiglxdisplay/Sources.pp b/panda/src/sgiglxdisplay/Sources.pp
index 94f55061a9..0af000ac01 100644
--- a/panda/src/sgiglxdisplay/Sources.pp
+++ b/panda/src/sgiglxdisplay/Sources.pp
@@ -1,5 +1,4 @@
-#define DIRECTORY_IF_SGIGL yes
-#define DIRECTORY_IF_GLX yes
+#define BUILD_DIRECTORY $[and $[HAVE_SGIGL],$[HAVE_GLX]]
 
 #define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
                    dtoolutil:c dtoolbase:c dtool:m
diff --git a/panda/src/vrpn/Sources.pp b/panda/src/vrpn/Sources.pp
index aedc8b807c..c7b3feec37 100644
--- a/panda/src/vrpn/Sources.pp
+++ b/panda/src/vrpn/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_VRPN yes
+#define BUILD_DIRECTORY $[HAVE_VRPN]
 
 #define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
                    dtoolutil:c dtoolbase:c dtool:m
diff --git a/panda/src/wcrdisplay/Sources.pp b/panda/src/wcrdisplay/Sources.pp
index f0b8d927cf..733c4044d5 100644
--- a/panda/src/wcrdisplay/Sources.pp
+++ b/panda/src/wcrdisplay/Sources.pp
@@ -1,5 +1,4 @@
-#define DIRECTORY_IF_WCR yes
-#define DIRECTORY_IF_CHROMIUM yes
+#define BUILD_DIRECTORY $[HAVE_WCR]
 
 #define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
                    dtoolutil:c dtoolbase:c dtool:m
diff --git a/panda/src/wdxdisplay/Sources.pp b/panda/src/wdxdisplay/Sources.pp
index 6b99cdfe19..099c5f2f36 100644
--- a/panda/src/wdxdisplay/Sources.pp
+++ b/panda/src/wdxdisplay/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_DX yes
+#define BUILD_DIRECTORY $[HAVE_DX]
 
 #define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
                    dtoolutil:c dtoolbase:c dtool:m
diff --git a/panda/src/wdxdisplay8/Sources.pp b/panda/src/wdxdisplay8/Sources.pp
index 29d58f1861..b74035a8cb 100644
--- a/panda/src/wdxdisplay8/Sources.pp
+++ b/panda/src/wdxdisplay8/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_DX yes
+#define BUILD_DIRECTORY $[HAVE_DX]
 
 #define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
                    dtoolutil:c dtoolbase:c dtool:m
diff --git a/panda/src/wgldisplay/Sources.pp b/panda/src/wgldisplay/Sources.pp
index 6d8ea79eb8..fb8787bd9d 100644
--- a/panda/src/wgldisplay/Sources.pp
+++ b/panda/src/wgldisplay/Sources.pp
@@ -1,5 +1,4 @@
-#define DIRECTORY_IF_GL yes
-#define DIRECTORY_IF_WGL yes
+#define BUILD_DIRECTORY $[HAVE_WGL]
 
 #define USE_GL yes
 
diff --git a/pandatool/src/gtk-stats/Sources.pp b/pandatool/src/gtk-stats/Sources.pp
index 0a7c669ed1..4fa1ca1714 100644
--- a/pandatool/src/gtk-stats/Sources.pp
+++ b/pandatool/src/gtk-stats/Sources.pp
@@ -1,6 +1,5 @@
-#define DIRECTORY_IF_GTKMM yes
+#define BUILD_DIRECTORY $[and $[HAVE_GTKMM],$[HAVE_NET]]
 #define USE_GTKMM yes
-#define DIRECTORY_IF_NET yes
 #define USE_NET yes
 
 #begin bin_target
diff --git a/pandatool/src/gtkbase/Sources.pp b/pandatool/src/gtkbase/Sources.pp
index eb7eb1eec4..82939227e0 100644
--- a/pandatool/src/gtkbase/Sources.pp
+++ b/pandatool/src/gtkbase/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_GTKMM yes
+#define BUILD_DIRECTORY $[HAVE_GTKMM]
 #define USE_GTKMM yes
 
 #begin ss_lib_target
diff --git a/pandatool/src/maya/Sources.pp b/pandatool/src/maya/Sources.pp
index 4cd966dc49..280a937738 100644
--- a/pandatool/src/maya/Sources.pp
+++ b/pandatool/src/maya/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_MAYA yes
+#define BUILD_DIRECTORY $[HAVE_MAYA]
 
 #begin ss_lib_target
   #define USE_MAYA yes
diff --git a/pandatool/src/mayaegg/Sources.pp b/pandatool/src/mayaegg/Sources.pp
index 59305f774f..c266d7972e 100644
--- a/pandatool/src/mayaegg/Sources.pp
+++ b/pandatool/src/mayaegg/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_MAYA yes
+#define BUILD_DIRECTORY $[HAVE_MAYA]
 
 #begin ss_lib_target
   #define USE_MAYA yes
diff --git a/pandatool/src/mayaprogs/Sources.pp b/pandatool/src/mayaprogs/Sources.pp
index db46d02ba4..a8577e578a 100644
--- a/pandatool/src/mayaprogs/Sources.pp
+++ b/pandatool/src/mayaprogs/Sources.pp
@@ -1,4 +1,4 @@
-#define DIRECTORY_IF_MAYA yes
+#define BUILD_DIRECTORY $[HAVE_MAYA]
 
 #define binary_name maya2egg
 
diff --git a/pandatool/src/pstatserver/Sources.pp b/pandatool/src/pstatserver/Sources.pp
index 8e4a720585..9373ffcf38 100644
--- a/pandatool/src/pstatserver/Sources.pp
+++ b/pandatool/src/pstatserver/Sources.pp
@@ -1,5 +1,4 @@
-#define DIRECTORY_IF_NET yes
-#define USE_NET yes
+#define BUILD_DIRECTORY $[HAVE_NET]
 
 #begin ss_lib_target
   #define TARGET pstatserver
diff --git a/pandatool/src/text-stats/Sources.pp b/pandatool/src/text-stats/Sources.pp
index f12705850e..35e8f7e79a 100644
--- a/pandatool/src/text-stats/Sources.pp
+++ b/pandatool/src/text-stats/Sources.pp
@@ -1,5 +1,4 @@
-#define DIRECTORY_IF_NET yes
-#define USE_NET yes
+#define BUILD_DIRECTORY $[HAVE_NET]
 
 #begin bin_target
   #define TARGET text-stats
diff --git a/pandatool/src/xfile/Sources.pp.disabled b/pandatool/src/xfile/Sources.pp
similarity index 88%
rename from pandatool/src/xfile/Sources.pp.disabled
rename to pandatool/src/xfile/Sources.pp
index 80ed7df7b5..2eec678b88 100644
--- a/pandatool/src/xfile/Sources.pp.disabled
+++ b/pandatool/src/xfile/Sources.pp
@@ -1,4 +1,7 @@
-#define DIRECTORY_IF_DX yes
+
+// This package is temporarily disabled.
+#define BUILD_DIRECTORY
+//#define BUILD_DIRECTORY $[HAVE_DX]
 #define USE_DX yes
 
 #begin ss_lib_target
diff --git a/pandatool/src/xfileprogs/Sources.pp.disabled b/pandatool/src/xfileprogs/Sources.pp
similarity index 88%
rename from pandatool/src/xfileprogs/Sources.pp.disabled
rename to pandatool/src/xfileprogs/Sources.pp
index e6ae1f3001..2561601303 100644
--- a/pandatool/src/xfileprogs/Sources.pp.disabled
+++ b/pandatool/src/xfileprogs/Sources.pp
@@ -1,4 +1,7 @@
-#define DIRECTORY_IF_DX yes
+
+// This package is temporarily disabled.
+#define BUILD_DIRECTORY
+//#define BUILD_DIRECTORY $[HAVE_DX]
 #define USE_DX yes
 
 #begin bin_target