android: Print error when trying to build on 32-bit host.

build/android/envsetup_functions.sh

Index: build/android/envsetup_functions.sh
diff --git a/build/android/envsetup_functions.sh b/build/android/envsetup_functions.sh
index 16ec004227aec6d8d547d3f810c8ecc3f2d4514b..a45c9e9898dcbd2295f3c3a14c3fc359bb545060 100755
--- a/build/android/envsetup_functions.sh
+++ b/build/android/envsetup_functions.sh
@@ -157,6 +157,7 @@ common_gyp_vars() {
 print_usage() {
   echo "usage: ${0##*/} [--target-arch=value] [--help]" >& 2
   echo "--target-arch=value     target CPU architecture (arm=default, x86)" >& 2
+  echo "--try-32bit-host        try building a 32-bit host architecture" >&2
   echo "--help                  this help" >& 2
 }
 
@@ -167,11 +168,15 @@ print_usage() {
 # --help          Prints out help message.
 ################################################################################
 process_options() {
+  try_32bit_host_build=
   while [[ $1 ]]; do
     case "$1" in
       --target-arch=*)
         target_arch="$(echo "$1" | sed 's/^[^=]*=//')"
         ;;
+      --try-32bit-host)
+        try_32bit_host_build=true
+        ;;
       --help)
         print_usage
         return 1