diff --git a/Makefile b/Makefile
index 9ab7d99d7d..77ca4a00da 100644
--- a/Makefile
+++ b/Makefile
@@ -209,6 +209,7 @@ unexport CFLAGS
 unexport CXXFLAGS
 unexport GREP_OPTIONS
 unexport CONFIG_SITE
+unexport QMAKESPEC
 
 GNU_HOST_NAME:=$(shell support/gnuconfig/config.guess)