Add target specific option to skip wallpapers from build

...and enable this for vega

Change-Id: I4fbe52dc0c6ffb6b732046f1579824317d9ea449
diff --git a/products/common.mk b/products/common.mk
index 64a0268..a1f8629 100644
--- a/products/common.mk
+++ b/products/common.mk
@@ -37,11 +37,16 @@
     CMParts \
     CMStats \
     CMUpdateNotify \
-    CMWallpapers \
     DSPManager \
     libcyanogen-dsp \
     Pacman
 
+# make wallpapers optional for low-storage-devices
+ifneq ($(PRODUCT_SKIP_WALLPAPERS),true)
+PRODUCT_PACKAGES += \
+    CMWallpapers
+endif
+
 # Extra tools in CyanogenMod
 PRODUCT_PACKAGES += \
     openvpn
diff --git a/products/cyanogen_vega.mk b/products/cyanogen_vega.mk
index 76144b3..18306c7 100644
--- a/products/cyanogen_vega.mk
+++ b/products/cyanogen_vega.mk
@@ -1,7 +1,8 @@
 $(call inherit-product, device/advent/vega/vega.mk)
 
-# skips themes and keeps the resulting rom tiny so it fits on /system/ with all languages included
-PRODUCT_SPECIFIC_DEFINES += SKIP_THEMES=true
+# skips themes and wallpaper to keep the resulting rom tiny so it fits on /system/ with all languages included
+PRODUCT_SKIP_THEMES=true
+PRODUCT_SKIP_WALLPAPERS=true
 
 # Inherit some common cyanogenmod stuff.
 $(call inherit-product, vendor/cyanogen/products/common_full.mk)
diff --git a/products/themes.mk b/products/themes.mk
index 856ab1f..03ef574 100644
--- a/products/themes.mk
+++ b/products/themes.mk
@@ -1,6 +1,6 @@
 # Theme packages
 
-ifneq ($(SKIP_THEMES),true)
+ifneq ($(PRODUCT_SKIP_THEMES),true)
 PRODUCT_PACKAGES += \
        Androidian \
        Cyanbread