Restore rbenv support

shell/rbenv

@@ -1,9 +1,17 @@
-# rbenv
+# vim: ft=sh
+# shellcheck shell=bash
+
 test -d "/opt/rbenv" && RBENV_ROOT="/opt/rbenv"
 test -d "$HOME/.rbenv" && RBENV_ROOT="$HOME/.rbenv"
 export RBENV_ROOT
 
 [[ -n "$RBENV_ROOT" ]] && PATH="$RBENV_ROOT/bin:$PATH"
 
-which rbenv 2>&1 >/dev/null && eval "$(rbenv init -)"
-export PATH
+_has-rbenv() {
+    type rbenv >/dev/null 2>&1
+}
+
+if _has-rbenv; then
+    eval "$(rbenv init -)"
+    export PATH
+fi

shell/ruby

@@ -8,7 +8,7 @@ _gem_home() {
     export PATH
 }
 
-if ! _has-chruby; then
+if ! _has-chruby && ! _has-rbenv; then
     _gem_home
 fi