diff --git a/panda/src/pipeline/Sources.pp b/panda/src/pipeline/Sources.pp
index f8ec79e9c5..f5245785f2 100644
--- a/panda/src/pipeline/Sources.pp
+++ b/panda/src/pipeline/Sources.pp
@@ -11,7 +11,7 @@
   #define COMBINED_SOURCES $[TARGET]_composite1.cxx $[TARGET]_composite2.cxx
 
   #define SOURCES \
-    ThreadSimpleImpl_no_opt_.cxx \
+    threadSimpleImpl_no_opt_.cxx \
     blockerSimple.h blockerSimple.I \
     conditionVar.h conditionVar.I \
     conditionVarDebug.h conditionVarDebug.I \