diff --git a/aegisub/Makefile.target b/aegisub/Makefile.target
index 7c7866e51..1e878c160 100644
--- a/aegisub/Makefile.target
+++ b/aegisub/Makefile.target
@@ -181,7 +181,7 @@ endif
 	$(CXX_ENV) $(BIN_CXX) $(CFLAGS_DEP) $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $<
 
 $(PRECOMPILED_HEADER_NAME).gch: $(PRECOMPILED_HEADER_NAME)
-	$(CXX_ENV) $(BIN_CXX) $(CPPFLAGS) $(CXXFLAGS) $<
+	$(CXX_ENV) $(BIN_CXX) $(CPPFLAGS) $(CXXFLAGS) -x c++-header $<