diff --git a/core/main.mk b/core/main.mk
index 41e2801..3bb8c04 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -175,7 +175,7 @@
 #
 # For Java 1.7, we require OpenJDK on linux and Oracle JDK on Mac OS.
 requires_openjdk := false
-ifeq ($(HOST_OS), linux)
+ifeq ($(BUILD_OS),linux)
 requires_openjdk := true
 endif