ninja: Add a friendlier error message if no prebuilt binary is found.

ninja

 #!/bin/bash
 
 # Copyright (c) 2012 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 OS="$(uname -s)"
 THIS_DIR="$(dirname "${0}")"
 
+function print_help() {
+  echo "No prebuilt ninja binary was found for this system."

[Lei Zhang, 2012/12/10 20:34:45]

you can also:

cat << __EOF
here is
my
message
__EOF

[Nico, 2012/12/11 04:49:34]

Done.

+  echo "Try building your own binary by doing:"
+  echo "  cd ~"
+  echo "  git clone https://github.com/martine/ninja.git"
+  echo "  cd ninja"
+  echo "  git checkout v1.0.0"
+  echo "  ./bootstrap.py"
+  echo "Then add ~/ninja/ to your PATH."
+}
+
 if [ "${OS}" = "Linux" ]; then
-  exec "${THIS_DIR}/ninja-linux64" "$@"
+  machine=$(getconf LONG_BIT)
+  if [ "$machine" = "64" ]; then
+    exec "${THIS_DIR}/ninja-linux64" "$@"
+  else
+    echo "Unsupported machine ${machine}"
+    print_help
+    exit 1
+  fi
 elif [ "${OS}" = "Darwin" ]; then
   exec "${THIS_DIR}/ninja-mac" "$@"
 elif [[ ${OS} == CYGWIN* ]]; then
   exec cmd.exe /c `cygpath -t windows $0`.exe "$@"
 elif [[ ${OS} == MINGW32* ]]; then
   cmd.exe //c $0.exe "$@"
 else
   echo "Unsupported OS ${OS}"
+  print_help
   exit 1
 fi
-