diff --git a/openscad.pro b/openscad.pro
index 96a0a2a2..a8f3d175 100644
--- a/openscad.pro
+++ b/openscad.pro
@@ -171,6 +171,13 @@ CONFIG(mingw-cross-env) {
   include(mingw-cross-env.pri)
 }
 
+win32 {
+  FLEXSOURCES = src/lexer.l
+  BISONSOURCES = src/parser.y
+} else {
+  LEXSOURCES += src/lexer.l
+  YACCSOURCES += src/parser.y
+}
 FLEXSOURCES = src/lexer.l
 BISONSOURCES = src/parser.y