vendor/cm: Create CM_PLATFORM_SDK_VERSION.

Change-Id: I7126b1ac93fbe3e0d5542279cb1f96dfc214bb23
diff --git a/config/common.mk b/config/common.mk
index cfd735d..85a2173 100644
--- a/config/common.mk
+++ b/config/common.mk
@@ -322,9 +322,23 @@
 # by default, do not update the recovery with system updates
 PRODUCT_PROPERTY_OVERRIDES += persist.sys.recovery_update=false
 
+ifndef CM_PLATFORM_SDK_VERSION
+  # This is the canonical definition of the SDK version, which defines
+  # the set of APIs and functionality available in the platform.  It
+  # is a single integer that increases monotonically as updates to
+  # the SDK are released.  It should only be incremented when the APIs for
+  # the new release are frozen (so that developers don't write apps against
+  # intermediate builds).
+  CM_PLATFORM_SDK_VERSION := 1
+endif
+
 PRODUCT_PROPERTY_OVERRIDES += \
   ro.cm.display.version=$(CM_DISPLAY_VERSION)
 
+# CyanogenMod Platform SDK Version
+PRODUCT_PROPERTY_OVERRIDES += \
+  ro.cm.build.version.plat.sdk=$(CM_PLATFORM_SDK_VERSION)
+
 -include $(WORKSPACE)/build_env/image-auto-bits.mk
 
 -include vendor/cyngn/product.mk