diff --git a/make/platform.mk b/make/platform.mk
index bf161fdd..117b4dc0 100644
--- a/make/platform.mk
+++ b/make/platform.mk
@@ -18,6 +18,14 @@ $(eval $(call try_include,$(JWBDIR)/make/pre-local.mk))
 $(eval $(call try_include,$(TOPDIR)/make/pre-local.mk))
 $(eval $(call try_include,pre-local.mk))
 
+ifdef PREREQ_RUN_ADD
+  # If PREREQ_RUN_ADD was defined in pre-local.mk, set these potentially cached
+  # paths up for fresh calculation in ldlibpath.mk / py-path.mk
+  undefine JW_PKG_EXE_PATH
+  undefine JW_PKG_LD_LIBRARY_PATH
+  undefine JW_PKG_PYTHON_PATH
+  PREREQ_RUN                += $(PREREQ_RUN_ADD)
+endif
 
 # -- What do I know about myself?
 VERSION_FILE                ?= $(firstword $(wildcard VERSION) $(TOPDIR)/VERSION)