Patch to provide pex_run_in_environment.

Patch to provide pex_run_in_environment.

	* include/libiberty.h: Declare pex_run_in_environment.

libiberty:

	* pex-common.c: New function pex_run_in_environment.
	* pex-common.h: Add environment parameter to exec_child.
	* pex-msdos.c: Add environment parameter to pex_msdos_exec_child.
	* pex-djgpp.c: Add environment parameter to pex_djgpp_exec_child.
	(pex_djgpp_exec_child): Pass environment to child process.
	* pex-unix.c: Add environment parameter to pex_unix_exec_child.
	(pex_unix_exec_child): Pass environment to child process.
	* pex-win32.c: Add environment parameter to pex_win32_exec_child.
	New function env_compare for comparing VAR=VALUE pairs.
	(win32_spawn): Assemble environment block and pass to CreateProcess.
	(spawn_script): Pass environment through to win32_spawn.
	(pex_win32_exec_child): Pass environment through to spawn_script and
	win32_spawn.
	* functions.texi: Regenerate.
	* pexecute.txh: Document pex_run_in_environment.

From-SVN: r114302