diff --git a/direct/.gitignore b/direct/.gitignore
index 9ecbb69fa0..97b7fbcf49 100644
--- a/direct/.gitignore
+++ b/direct/.gitignore
@@ -1,5 +1,8 @@
 *.pyc
 /__init__.py
-/built/
+# These are files that are generated within the source tree by the
+# ppremake system.
 Makefile
 pp.dep
+/built/
+Opt?-*
diff --git a/dtool/.gitignore b/dtool/.gitignore
index b570f28ee1..d306650d5e 100644
--- a/dtool/.gitignore
+++ b/dtool/.gitignore
@@ -1,4 +1,7 @@
-/built/
 /dtool_config.h
+# These are files that are generated within the source tree by the
+# ppremake system.
 Makefile
 pp.dep
+/built/
+Opt?-*
diff --git a/panda/.gitignore b/panda/.gitignore
index 0d20b6487c..3fbb4b2955 100644
--- a/panda/.gitignore
+++ b/panda/.gitignore
@@ -1 +1,7 @@
 *.pyc
+# These are files that are generated within the source tree by the
+# ppremake system.
+Makefile
+pp.dep
+/built/
+Opt?-*
diff --git a/pandatool/.gitignore b/pandatool/.gitignore
index 8a32c60a80..692e733aa2 100644
--- a/pandatool/.gitignore
+++ b/pandatool/.gitignore
@@ -1,3 +1,6 @@
-/built/
+# These are files that are generated within the source tree by the
+# ppremake system.
 Makefile
 pp.dep
+/built/
+Opt?-*