* module/ice-9/boot-9.scm:
* module/ice-9/psyntax.scm (syntax-module, syntax-local-binding)
(syntax-locally-bound-identifiers): After boot, move these definitions
to a new (system syntax) module.
* module/ice-9/psyntax-pp.scm: Regenerate.
* doc/ref/api-macros.texi: Add some words about syntax-module and
friends being in (system syntax).
* module/ice-9/boot-9.scm (syntax-local-binding): New binding.
* module/ice-9/psyntax.scm: Locally define a fluid that holds the
"transformer environment". with-transformer-environment calls a
procedure with the transformer environment, or raises an error if
called outside the extent of a transformer. Bind
transformer-environment in expand-macro.
(resolve-identifier): Backport this helper from master.
(syntax-local-binding): New procedure to return binding information of
a bound identifier (a lexical, macro, a pattern variable, a displaced
lexical, a global, or some other form).
* module/ice-9/psyntax-pp.scm: Regenerate.
* doc/ref/api-macros.texi (Syntax Transformer Helpers): Add docs for
syntax-local-binding, and syntax-source, and move some other
descriptions to this new section.
* doc/ref/api-macros.texi: New file, documenting macros. Removed some
old cruft, and started documenting hygienic macros.
* doc/ref/api-procedures.texi: Moved macro things out of here.
* doc/ref/guile.texi: Separate macros from procedures.
* doc/ref/api-data.texi: Update some xrefs.
* doc/ref/Makefile.am: Add api-macros.texi.
