Multi Thread, Async Signal and Async Cancel safety documentation: intro

for  ChangeLog

	* manual/macros.texi: Introduce macros to document multi
	thread, asynchronous signal and asynchronous cancellation
	safety properties.
	* manual/intro.texi: Introduce the properties themselves.
MT-, AS- and AC-safety docs: manual/argp.texi

for ChangeLog

	* manual/argp.texi: Document MTASC-safety properties.
MT-, AS- and AC-safety docs: manual/arith.texi

for  ChangeLog

	* manual/arith.texi: Document MTASC-safety properties.
MT-, AS- and AC-safety docs: manual/charset.texi

for ChangeLog

	* manual/charset.texi: Document MTASC-safety properties.
MT-, AS- and AC-safety docs: manual/conf.texi

for ChangeLog

	* manual/conf.texi: Document MTASC-safety properties.
MT-, AS- and AC-safety docs: manual/crypt.texi

for ChangeLog

	* manual/crypt.texi: Document MTASC-safety properties.
MT-, AS- and AC-safety docs: manual/ctype.texi

for ChangeLog

	* manual/ctype.texi: Document MTASC-safety properties.
MT-, AS- and AC-safety docs: manual/debug.texi

for ChangeLog

	* manual/debug.texi: Document MTASC-safety properties.
MT-, AS- and AC-safety docs: manual/errno.texi

for ChangeLog

	* manual/errno.texi: Document MTASC-safety properties.
MT-, AS- and AC-safety docs: manual/filesys.texi

for ChangeLog

	* manual/filesys.texi: Document MTASC-safety properties.
MT-, AS- and AC-safety docs: manual/getopt.texi

for ChangeLog

	* manual/getopt.texi: Document MTASC-safety properties.
MT-, AS- and AC-safety docs: manual/libdl.texi

for ChangeLog

	* manual/libdl.texi: New.
MT-, AS- and AC-safety docs: manual/math.texi

for ChangeLog

	* manual/math.texi: Document MTASC-safety properties.
MT-, AS- and AC-safety docs: manual/memory.texi

for ChangeLog

	* manual/memory.texi: Document MTASC-safety properties.
MT-, AS- and AC-safety docs: manual/message.texi

for ChangeLog

	* manual/message.texi: Document MTASC-safety properties.
MT-, AS- and AC-safety docs: manual/job.texi

for ChangeLog

	* manual/job.texi: Document MTASC-safety properties.
MT-, AS- and AC-safety docs: manual/lang.texi

for ChangeLog

	* manual/lang.texi: Document MTASC-safety properties.
MT-, AS- and AC-safety docs: manual/llio.texi

for ChangeLog

	* manual/llio.texi: Document MTASC-safety properties.
MT-, AS- and AC-safety docs: manual/locale.texi

for  ChangeLog

	* manual/locale.texi: Document MTASC-safety properties.
MT-, AS- and AC-safety docs: manual/pattern.texi

for ChangeLog

	* manual/pattern.texi: Document MTASC-safety properties.