Add ASAN_SYMBOLIZER_PATH for SANITIZE_HOST=address builds.

Bug: http://b/30877494
Test: source build/envsetup.sh && echo $ASAN_SYMBOLIZER_PATH --version
Change-Id: I669a5762cc2cea26c0c29f935abde6c14eb0ced7
diff --git a/envsetup.sh b/envsetup.sh
index 389fbb7..793f4b6 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -254,6 +254,9 @@
     local ANDROID_LLVM_BINUTILS=$(get_abs_build_var ANDROID_CLANG_PREBUILTS)/llvm-binutils-stable
     ANDROID_BUILD_PATHS=$ANDROID_BUILD_PATHS:$ANDROID_LLVM_BINUTILS
 
+    # Set up ASAN_SYMBOLIZER_PATH for SANITIZE_HOST=address builds.
+    export ASAN_SYMBOLIZER_PATH=$ANDROID_LLVM_BINUTILS/llvm-symbolizer
+
     # If prebuilts/android-emulator/<system>/ exists, prepend it to our PATH
     # to ensure that the corresponding 'emulator' binaries are used.
     case $(uname -s) in