ENV: move to new paths. (#507)

Move some stuff formerly in `Library/ENV` around:
- Move `Library/ENV/$XCODE_VERSION` to `Library/Homebrew/env/super` as they are
  all superenv wrappers and all symlinks to the same version. We never needed
  the "separate shims for separate versions" functionality and it just adds
  confusion.
- Move `Library/ENV/pkgconfig` to `Library/Homebrew/env/pkgconfig` to get more
  things under `Library/Homebrew`
- Move `Library/ENV/scm` to `Library/scm` as these wrappers are not actually
  used by or related to superenv (or stdenv) in any way.

1 files changed, 120 insertions, 0 deletions

diff --git a/Library/Homebrew/shims/scm/git b/Library/Homebrew/shims/scm/git
new file mode 100755
index 000000000..10950ef07
--- /dev/null
+++ b/Library/Homebrew/shims/scm/git
@@ -0,0 +1,120 @@
+#!/bin/bash
+
+# This script because we support $GIT, $HOMEBREW_SVN, etc., Xcode-only and
+# no Xcode/CLT configurations. Order is careful to be what the user would want.
+
+set +o posix
+
+quiet_safe_cd() {
+  cd "$1" >/dev/null || { echo "Error: failed to cd to $1" >&2; exit 1; }
+}
+
+realpath() {
+  local path="$1"
+  local dir
+  local base
+  local dest
+
+  dir="$(quiet_safe_cd "${path%/*}/" && pwd -P)"
+  base="${path##*/}"
+  path="$dir/$base"
+
+  while [[ -L "$path" ]]
+  do
+    dest="$(readlink "$path")"
+    if [[ "$dest" = "/"* ]]
+    then
+      path="$dest"
+    else
+      path="$dir/$dest"
+    fi
+    dir="$(quiet_safe_cd "${path%/*}/" && pwd -P)"
+    base="${path##*/}"
+    path="$dir/$base"
+  done
+
+  echo "$path"
+}
+
+executable() {
+  local file="$1"
+  [[ -f "$file" && -x "$file" ]]
+}
+
+lowercase() {
+  echo "$1" | tr '[:upper:]' '[:lower:]'
+}
+
+safe_exec() {
+  local arg0="$1"
+  if ! executable "$arg0"
+  then
+    return
+  fi
+  # prevent fork-bombs
+  if [[ "$(lowercase "$arg0")" = "$SCM_FILE" || "$(realpath "$arg0")" = "$SCM_REAL" ]]
+  then
+    return
+  fi
+  if [[ "$HOMEBREW" = "print-path" ]]
+  then
+    echo "$arg0"
+    exit
+  fi
+  exec "$@"
+}
+
+SCM_FILE="${0##*/}"
+SCM_REAL="$(realpath "$0")"
+SCM_DIR="$(quiet_safe_cd "${SCM_REAL%/*}/" && pwd -P)"
+
+if [[ "$1" = --homebrew=* ]]
+then
+  HOMEBREW="${1:11}"
+  shift
+fi
+
+case "$(lowercase "$SCM_FILE")" in
+  git)
+    [[ -n "$HOMEBREW_GIT" ]] && safe_exec "$(which "$HOMEBREW_GIT")" "$@"
+    [[ -n "$GIT" ]] && safe_exec "$(which "$GIT")" "$@"
+    ;;
+  svn)
+    [[ -n "$HOMEBREW_SVN" ]] && safe_exec "$(which "$HOMEBREW_SVN")" "$@"
+    ;;
+esac
+
+brew_version="$(quiet_safe_cd "$SCM_DIR/../../../../bin" && pwd -P)/$SCM_FILE"
+safe_exec "$brew_version" "$@"
+
+IFS=$'\n'
+for path in $(/usr/bin/which -a "$SCM_FILE" 2>/dev/null)
+do
+  if [[ "$path" != "/usr/bin/$SCM_FILE" ]]
+  then
+    safe_exec "$path" "$@"
+  fi
+done
+
+if executable "/usr/bin/xcode-select"
+then
+  # xcode-select will return empty on no Xcode/CLT configuration.
+  #   /usr/bin/<tool> will be a popup stub under such configuration.
+  # xcrun hangs if xcode-select is set to "/"
+  xcode_path="$(/usr/bin/xcode-select -print-path 2>/dev/null)"
+  [[ -n "$xcode_path" ]] || popup_stub=1
+  if [[ -z "$popup_stub" && "$xcode_path" != "/" ]]
+  then
+    path="$(/usr/bin/xcrun -find "$SCM_FILE" 2>/dev/null)"
+    safe_exec "$path" "$@"
+  fi
+fi
+
+path="/Applications/Xcode.app/Contents/Developer/usr/bin/$SCM_FILE"
+safe_exec "$path" "$@"
+
+path="/usr/bin/$SCM_FILE"
+[[ -z "$popup_stub" ]] && safe_exec "$path" "$@"
+
+echo "You must: brew install $SCM_FILE" >&2
+exit 1