android-x86: do not build the emulator forcibly

If a target wants to build the emulator, it should set
in its BoardConfig.mk.

diff --git a/core/main.mk b/core/main.mk
index d424b25..5ed7686 100644 (file)
--- a/core/main.mk
+++ b/core/main.mk
@@ -199,7 +199,7 @@ else
   BUILD_EMULATOR := true
 endif
 else   # HOST_OS is not darwin
-  BUILD_EMULATOR := true
+  BUILD_EMULATOR ?= true
 endif  # HOST_OS is darwin
 endif