build: Add Bliss build support

Squashed also with the following changes:

  Author: Luca Stefani <luca020400@lineageos.org>
  Date:   Thu Aug 17 22:22:13 2017 +0200

    core: Include Bliss pathmap

  Change-Id: Ie25dee383cc5bc9bb6390cff2cb2460d526d80b6

  Author: Simon Shields <simon@lineageos.org>
  Date:   Fri Mar 2 12:55:47 2018 +1100

    build: unconditionally use bliss pathmap

    even if we're not building a bliss target, we need to
    use the bliss pathmap to make things like recovery and ril
    happy

  Change-Id: I974c30ad10d4ff5b7805c3df9c22010f1e002bf1

Change-Id: Iab8b2ef8b644a7bea10bfd28b99d9e69539b1357
diff --git a/envsetup.sh b/envsetup.sh
index 645f69b..d8cf3c8 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -137,6 +137,14 @@
         echo "Couldn't locate the top of the tree.  Try setting TOP." >&2
         return
     fi
+    if (echo -n $1 | grep -q -e "^bliss_") ; then
+        BLISS_BUILD=$(echo -n $1 | sed -e 's/^bliss_//g')
+        export BUILD_NUMBER=$( (date +%s%N ; echo $BLISS_BUILD; hostname) | openssl sha1 | sed -e 's/.*=//g; s/ //g' | cut -c1-10 )
+    else
+        BLISS_BUILD=
+    fi
+    export BLISS_BUILD
+
         TARGET_PRODUCT=$1 \
         TARGET_BUILD_VARIANT= \
         TARGET_BUILD_TYPE= \
@@ -623,6 +631,8 @@
         return 1
     fi
 
+    check_product $product
+
     TARGET_PRODUCT=$product \
     TARGET_BUILD_VARIANT=$variant \
     TARGET_PLATFORM_VERSION=$version \