diff --git a/dtool/pptempl/Template.gmsvc.pp b/dtool/pptempl/Template.gmsvc.pp
index 694f83f2f4..a60502409f 100644
--- a/dtool/pptempl/Template.gmsvc.pp
+++ b/dtool/pptempl/Template.gmsvc.pp
@@ -759,6 +759,7 @@ $[TAB] cp $[target_header] $[target_header].prebuilt
 #define source $[target].prebuilt
 $[target] : $[source]
 $[TAB] cp $[source] $[target]
+#define source $[target_header].prebuilt
 $[target_header] : $[source]
 $[TAB] cp $[source] $[target_header]
 #endif // HAVE_BISON
diff --git a/dtool/pptempl/Template.msvc.pp b/dtool/pptempl/Template.msvc.pp
index a6f617dc06..2894415fef 100644
--- a/dtool/pptempl/Template.msvc.pp
+++ b/dtool/pptempl/Template.msvc.pp
@@ -733,6 +733,7 @@ $[TAB] copy $[target_header] $[target_header].prebuilt
 #define source $[target].prebuilt
 $[target] : $[source]
 $[TAB] copy $[source] $[target]
+#define source $[target_header].prebuilt
 $[target_header] : $[source]
 $[TAB] copy $[source] $[target_header]
 #endif // HAVE_BISON
diff --git a/dtool/pptempl/Template.unix.pp b/dtool/pptempl/Template.unix.pp
index 95343c7869..8139922304 100644
--- a/dtool/pptempl/Template.unix.pp
+++ b/dtool/pptempl/Template.unix.pp
@@ -608,6 +608,7 @@ $[TAB]cp $[target_header] $[target_header].prebuilt
 #define source $[target].prebuilt
 $[target] : $[source]
 $[TAB]cp $[source] $[target]
+#define source $[target_header].prebuilt
 $[target_header] : $[source]
 $[TAB]cp $[source] $[target_header]
 #endif // HAVE_BISON