global: fix subshell detection in Bash 3.2

ble.pp

@@ -187,7 +187,7 @@ function ble/bin/.freeze-utility-path {
 
 # POSIX utilities
 
-_ble_init_posix_command_list=(sed date rm mkdir mkfifo sleep stty sort awk chmod grep man cat wc mv)
+_ble_init_posix_command_list=(sed date rm mkdir mkfifo sleep stty sort awk chmod grep man cat wc mv sh)
 function ble/.check-environment {
   if ! type "${_ble_init_posix_command_list[@]}" &>/dev/null; then
     local cmd commandMissing=
@@ -651,7 +651,7 @@ function ble/base/unload-for-reload {
   return 0
 }
 function ble/base/unload {
-  [[ $$ == $BASHPID ]] || return
+  ble/util/is-running-in-subshell && return 1
   local IFS=$' \t\n'
   ble/term/stty/TRAPEXIT
   ble/term/leave

src/edit.sh

@@ -3519,7 +3519,7 @@ function ble-edit/exec/restore-BASH_REMATCH {
 
 function ble/builtin/exit {
   local ext=${1-$?}
-  if ((BASHPID!=$$)) || [[ $_ble_decode_bind_state == none ]]; then
+  if ble/util/is-running-in-subshell || [[ $_ble_decode_bind_state == none ]]; then
     builtin exit "$ext"
     return
   fi

src/util.sh

@@ -895,6 +895,18 @@ else
   function ble/util/is-stdin-ready { false; }
 fi
 
+# Note: BASHPID は Bash-4.0 以上
+if ((_ble_bash>=40000)); then
+  function ble/util/is-running-in-subshell { [[ $$ != $BASHPID ]]; }
+else
+  function ble/util/is-running-in-subshell {
+    ((BASH_SUBSHELL)) && return 0
+    local bashpid= command='echo $PPID'
+    ble/util/assign bashpid 'ble/bin/sh -c "$command"'
+    [[ $$ != $bashpid ]]
+  }
+fi
+
 ## 関数 ble/util/openat fdvar redirect
 ##   "exec {fdvar}>foo" に該当する操作を実行します。
 ##   @param[out] fdvar