diff --git a/Makefile b/Makefile
index c07ff3dae5..2ee7f92aa9 100644
--- a/Makefile
+++ b/Makefile
@@ -431,6 +431,8 @@ unexport TERMINFO
 unexport MACHINE
 unexport O
 unexport GCC_COLORS
+unexport PLATFORM
+unexport OS
 
 GNU_HOST_NAME := $(shell support/gnuconfig/config.guess)