cmake_build: support SKIA_OUT and BUILDTYPE

cmake/cmake_build

Index: cmake/cmake_build
diff --git a/cmake/cmake_build b/cmake/cmake_build
index 2ff7a9c541bf5895c309358b8313f6d12612f4e1..0d45d7d7784b92a70b5458566a791d0678c17a15 100755
--- a/cmake/cmake_build
+++ b/cmake/cmake_build
@@ -10,9 +10,20 @@
 set -e
 set -x
 
-here=`dirname $0`
+fulldir() {
+    cd `dirname $1`
+    echo `pwd`
+}
+
+here=`fulldir $0`
 cores=32
 
+if [[ -z "$BUILDTYPE" || -z "$SKIA_OUT" ]]; then
+    echo "If you're a bot, you should be setting BUILDTYPE ($BUILDTYPE) and SKIA_OUT ($SKIA_OUT)."
+    echo "If you're not a bot, you don't want to run this script."
+    exit 1
+fi
+
 echo "Bootstrapping CMake"
 pushd $here/../third_party/externals/cmake
 ./bootstrap --parallel=$cores
@@ -20,7 +31,8 @@ make -j $cores
 popd
 
 echo "Building with bootstrapped CMake"
-pushd $here
-../third_party/externals/cmake/bin/cmake . -G Ninja
+mkdir -p $SKIA_OUT
+pushd $SKIA_OUT
+$here/../third_party/externals/cmake/bin/cmake -DCMAKE_BUILD_TYPE=$BUILDTYPE $here -G Ninja
 ninja skia  # The default also builds `example`, which I'm leaving a TODO for now.
 popd