diff --git a/3rdparty/Makefile.inc b/3rdparty/Makefile.inc
index 80dc126923..70f316b0c8 100644
--- a/3rdparty/Makefile.inc
+++ b/3rdparty/Makefile.inc
@@ -1,3 +1,3 @@
-THIRDPARTY_DIR = $(dir $(word 2, $(MAKEFILE_LIST)))
+THIRDPARTY_DIR := $(dir $(lastword $(MAKEFILE_LIST)))
 include $(THIRDPARTY_DIR)/everest/Makefile.inc
 include $(THIRDPARTY_DIR)/p256-m/Makefile.inc