[docker] Fix unmatched quote problem in here-document on older versions of bash

[hintonda]

Summary

When outputing usage, emit here-document directly instead of
saving in a variable first -- avoids problem with bash 3.2.57 where an
unmatched ' in the here-document results in the following error:

./build_docker_image.sh: line 135: unexpected EOF while looking for matching `''

bash --version
GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin16)

[ilya-biryukov]

Thanks for fixing that. I've only tested on bash 4.3.
Could you also update utils/docker/scripts/build_install_llvm.sh for consistency?

[hintonda]

• Apply here-document fix to all scripts for consistency.

[ilya-biryukov]

Thanks!

utils/docker/build_docker_image.sh

 set -e
 
 IMAGE_SOURCE=""
 DOCKER_REPOSITORY=""
 DOCKER_TAG=""
 BUILDSCRIPT_ARGS=""
 
 function show_usage() {
-  usage=$(cat << EOF
+  cat << EOF
 Usage: build_docker_image.sh [options] [-- [cmake_args]...]
 
 Available options:
   General:
     -h|--help               show this help message
   Docker-specific:
     -s|--source             image source dir (i.e. debian8, nvidia-cuda, etc)
     -d|--docker-repository  docker repository for the image

 $ ./build_docker_image.sh -s debian8 -d mydocker/clang-debian8 -t "latest" \ 
     -p clang -i stage2-install-clang -i stage2-install-clang-headers \ 
     -- \ 
     -DLLVM_TARGETS_TO_BUILD=Native -DCMAKE_BUILD_TYPE=Release \ 
     -DBOOTSTRAP_CMAKE_BUILD_TYPE=Release \ 
     -DCLANG_ENABLE_BOOTSTRAP=ON \ 
     -DCLANG_BOOTSTRAP_TARGETS="install-clang;install-clang-headers"
 EOF
-)
-  echo "$usage"
 }
 
 SEEN_INSTALL_TARGET=0
 while [[ $# -gt 0 ]]; do
   case "$1" in
     -h|--help)
       show_usage
       exit 0