diff --git a/freetype.pri b/freetype.pri
index 1f0f9655..0b13b742 100644
--- a/freetype.pri
+++ b/freetype.pri
@@ -14,8 +14,10 @@ FREETYPE_DIR = $$(FREETYPEDIR)
 
 !isEmpty(OPENSCAD_LIBRARIES_DIR) {
   isEmpty(FREETYPE_INCLUDEPATH) {
-    FREETYPE_INCLUDEPATH = $$OPENSCAD_LIBRARIES_DIR/include/freetype2
-    FREETYPE_LIBPATH = $$OPENSCAD_LIBRARIES_DIR/lib
+    exists($$OPENSCAD_LIBRARIES_DIR/include/freetype2) {
+      FREETYPE_INCLUDEPATH = $$OPENSCAD_LIBRARIES_DIR/include/freetype2
+      FREETYPE_LIBPATH = $$OPENSCAD_LIBRARIES_DIR/lib
+    }
   }
 }
 
diff --git a/harfbuzz.pri b/harfbuzz.pri
index 2a60096f..f3022bbd 100644
--- a/harfbuzz.pri
+++ b/harfbuzz.pri
@@ -14,8 +14,10 @@ HARFBUZZ_DIR = $$(HARFBUZZDIR)
 
 !isEmpty(OPENSCAD_LIBRARIES_DIR) {
   isEmpty(HARFBUZZ_INCLUDEPATH) {
-    HARFBUZZ_INCLUDEPATH = $$OPENSCAD_LIBRARIES_DIR/include/harfbuzz
-    HARFBUZZ_LIBPATH = $$OPENSCAD_LIBRARIES_DIR/lib
+    exists($$OPENSCAD_LIBRARIES_DIR/include/harfbuzz) {
+      HARFBUZZ_INCLUDEPATH = $$OPENSCAD_LIBRARIES_DIR/include/harfbuzz
+      HARFBUZZ_LIBPATH = $$OPENSCAD_LIBRARIES_DIR/lib
+    }
   }
 }