Support conditional package installation with `--if <test>`

bin/ruby-build

@@ -93,15 +93,15 @@ file_is_not_empty() {
 }
 
 install_package() {
-  install_package_using "tarball" 1 $*
+  install_package_using "tarball" 1 "$@"
 }
 
 install_git() {
-  install_package_using "git" 2 $*
+  install_package_using "git" 2 "$@"
 }
 
 install_svn() {
-  install_package_using "svn" 2 $*
+  install_package_using "svn" 2 "$@"
 }
 
 install_package_using() {
@@ -110,10 +110,22 @@ install_package_using() {
   local package_name="$3"
   shift 3
 
+  local fetch_args=( "$package_name" "${@:1:$package_type_nargs}" )
+  local make_args=( "$package_name" )
+  local arg last_arg
+
+  for arg in "${@:$(( $package_type_nargs + 1 ))}"; do
+    if [ "$last_arg" = "--if" ]; then
+      "$arg" || return 0
+    elif [ "$arg" != "--if" ]; then
+      make_args["${#make_args[@]}"]="$arg"
+    fi
+    last_arg="$arg"
+  done
+
   pushd "$BUILD_PATH" >&4
-  "fetch_${package_type}" "$package_name" $*
-  shift $(($package_type_nargs))
-  make_package "$package_name" $*
+  "fetch_${package_type}" "${fetch_args[@]}"
+  make_package "${make_args[@]}"
   popd >&4
 
   { echo "Installed ${package_name} to ${PREFIX_PATH}"

share/ruby-build/2.0.0-dev

-if has_broken_mac_openssl; then
-  install_package "openssl-1.0.1c" "https://www.openssl.org/source/openssl-1.0.1c.tar.gz#ae412727c8c15b67880aef7bd2999b2e" mac_openssl
-fi
-
+install_package "openssl-1.0.1c" "https://www.openssl.org/source/openssl-1.0.1c.tar.gz#ae412727c8c15b67880aef7bd2999b2e" mac_openssl --if has_broken_mac_openssl
 install_git "ruby-2.0.0-dev" "https://github.com/ruby/ruby.git" "trunk" autoconf standard verify_openssl

share/ruby-build/2.0.0-preview1

-if has_broken_mac_openssl; then
-  install_package "openssl-1.0.1c" "https://www.openssl.org/source/openssl-1.0.1c.tar.gz#ae412727c8c15b67880aef7bd2999b2e" mac_openssl
-fi
-
+install_package "openssl-1.0.1c" "https://www.openssl.org/source/openssl-1.0.1c.tar.gz#ae412727c8c15b67880aef7bd2999b2e" mac_openssl --if has_broken_mac_openssl
 install_package "yaml-0.1.4" "http://pyyaml.org/download/libyaml/yaml-0.1.4.tar.gz#36c852831d02cf90508c29852361d01b"
 install_package "ruby-2.0.0-preview1" "http://ftp.ruby-lang.org/pub/ruby/2.0/ruby-2.0.0-preview1.tar.gz#c7d73f3ddb6d25e7733626ddbad04158" standard verify_openssl

share/ruby-build/2.0.0-preview2

-if has_broken_mac_openssl; then
-  install_package "openssl-1.0.1c" "https://www.openssl.org/source/openssl-1.0.1c.tar.gz#ae412727c8c15b67880aef7bd2999b2e" mac_openssl
-fi
-
+install_package "openssl-1.0.1c" "https://www.openssl.org/source/openssl-1.0.1c.tar.gz#ae412727c8c15b67880aef7bd2999b2e" mac_openssl --if has_broken_mac_openssl
 install_package "ruby-2.0.0-preview2" "http://ftp.ruby-lang.org/pub/ruby/2.0/ruby-2.0.0-preview2.tar.gz#eaddcbf63dc775708de45c7a81ab54b9" standard verify_openssl

share/ruby-build/2.0.0-rc1

-if has_broken_mac_openssl; then
-  install_package "openssl-1.0.1c" "https://www.openssl.org/source/openssl-1.0.1c.tar.gz#ae412727c8c15b67880aef7bd2999b2e" mac_openssl
-fi
-
+install_package "openssl-1.0.1c" "https://www.openssl.org/source/openssl-1.0.1c.tar.gz#ae412727c8c15b67880aef7bd2999b2e" mac_openssl --if has_broken_mac_openssl
 install_package "ruby-2.0.0-rc1" "http://ftp.ruby-lang.org/pub/ruby/2.0/ruby-2.0.0-rc1.tar.gz#7d587dde85e0edf7a2e4f6783e6c0e2e" standard verify_openssl

share/ruby-build/2.0.0-rc2

-if has_broken_mac_openssl; then
-  install_package "openssl-1.0.1c" "https://www.openssl.org/source/openssl-1.0.1c.tar.gz#ae412727c8c15b67880aef7bd2999b2e" mac_openssl
-fi
-
+install_package "openssl-1.0.1c" "https://www.openssl.org/source/openssl-1.0.1c.tar.gz#ae412727c8c15b67880aef7bd2999b2e" mac_openssl --if has_broken_mac_openssl
 install_package "ruby-2.0.0-rc2" "http://ftp.ruby-lang.org/pub/ruby/2.0/ruby-2.0.0-rc2.tar.gz#9d5e6f26db7c8c3ddefc81fdb19bd41a" standard verify_openssl