build: Add extension helper generation to cmake

Change-Id: Id93ead148d5b0beb23ee5d9f1bc7e8fc727aa46e
diff --git a/build-android/android-generate.sh b/build-android/android-generate.sh
index c0c05e4..aa4bef1 100755
--- a/build-android/android-generate.sh
+++ b/build-android/android-generate.sh
@@ -34,5 +34,6 @@
 ( cd generated/include; python3 ../../../scripts/lvl_genvk.py -registry ../../../scripts/vk.xml vk_loader_extensions.h )
 ( cd generated/include; python3 ../../../scripts/lvl_genvk.py -registry ../../../scripts/vk.xml vk_loader_extensions.c )
 ( cd generated/include; python3 ../../../scripts/lvl_genvk.py -registry ../../../scripts/vk.xml vk_layer_dispatch_table.h )
+( cd generated/include; python3 ../../../scripts/lvl_genvk.py -registry ../../../scripts/vk.xml vk_extension_helper.h )
 
 exit 0