first_stage_init: add console

Start and wait on a console if androidboot.first_stage_console=1 is
present on the kernel command line. This only works on eng and
userdebug builds.

Change-Id: I978e9390a89509431b399ea58b284736b27eeb1b
diff --git a/init/Android.mk b/init/Android.mk
index b24f757..9017772 100644
--- a/init/Android.mk
+++ b/init/Android.mk
@@ -8,6 +8,7 @@
 
 ifneq (,$(filter userdebug eng,$(TARGET_BUILD_VARIANT)))
 init_options += \
+    -DALLOW_FIRST_STAGE_CONSOLE=1 \
     -DALLOW_LOCAL_PROP_OVERRIDE=1 \
     -DALLOW_PERMISSIVE_SELINUX=1 \
     -DREBOOT_BOOTLOADER_ON_PANIC=1 \
@@ -15,6 +16,7 @@
     -DDUMP_ON_UMOUNT_FAILURE=1
 else
 init_options += \
+    -DALLOW_FIRST_STAGE_CONSOLE=0 \
     -DALLOW_LOCAL_PROP_OVERRIDE=0 \
     -DALLOW_PERMISSIVE_SELINUX=0 \
     -DREBOOT_BOOTLOADER_ON_PANIC=0 \