diff --git a/Makefile b/Makefile
index ea80f00..6eceeb3 100644
--- a/Makefile
+++ b/Makefile
@@ -21,7 +21,7 @@
 ifeq ("", "$(CROSS_COMPILE)")
   MK_ARCH="${shell uname -m}"
 else
-  MK_ARCH="${shell echo $(CROSS_COMPILE) | sed -n 's/^\s*\([^\/]*\/\)*\([^-]*\)-\S*/\2/p'}"
+  MK_ARCH="${shell echo $(CROSS_COMPILE) | sed -n 's/^[[:space:]]*\([^\/]*\/\)*\([^-]*\)-[^[:space:]]*/\2/p'}"
 endif
 unexport HOST_ARCH
 ifeq ("x86_64", $(MK_ARCH))