utils: build-kitkat smarter aosp invocation

* Attempt to find the aosp binary with the following priority:
  1. If AOSP_BIN is set, use that
  2. If aosp is found in the shell $PATH
  3. Grab it from the web

tests/build-kitkat.sh

@@ -4,8 +4,6 @@
 #
 set -ex
 
-AOSP_BIN=${AOSP_BIN:-aosp}
-
 if [ "$1" = "docker" ]; then
     branch=android-4.4.4_r2.0.1
     cpus=$(grep ^processor /proc/cpuinfo | wc -l)
@@ -19,6 +17,30 @@ if [ "$1" = "docker" ]; then
     lunch aosp_arm-eng
     make -j $cpus
 else
+    aosp_url="https://raw.githubusercontent.com/kylemanna/docker-aosp/master/utils/aosp"
+    args="run.sh docker"
     export AOSP_EXTRA_ARGS="-v $(readlink -f $0):/usr/local/bin/run.sh:ro"
-    $AOSP_BIN run.sh docker
+
+    #
+    # Try to invoke the aosp wrapper with the following priority:
+    #
+    # 1. If AOSP_BIN is set, use that
+    # 2. If aosp is found in the shell $PATH
+    # 3. Grab it from the web
+    #
+    if [ -n "$AOSP_BIN" ]; then
+        $AOSP_BIN $args
+    elif [ -x "../utils/aosp" ]; then
+        ../utils/aosp $args
+    elif [ -n "$(type -P aosp)" ]; then
+        aosp $args
+    else
+        if [ -n "$(type -P curl)" ]; then
+            bash <(curl -s $aosp_url) $args
+        elif [ -n "$(type -P wget)" ]; then
+            bash <(wget -q $aosp_url -O -) $args
+        else
+            echo "Unable to run the aosp binary"
+        fi
+    fi
 fi