Add external modules
* configure.ac: Add libtool support and module Makefiles.
* src/Makefile.in: Support libtool.
* src/alloc.c (mark_object): Mark the doc field of Lisp_Subr as object.
* src/doc.c (doc_is_from_module_p, get_doc_string, reread_doc_file)
(store_function_docstring, build_file_p, Fsnarf_documentation):
Support docstrings for external modules.
* src/lisp.h: Make the doc field of Lisp_Subr a Lisp_Object.
* src/lread.c (Fget_load_suffixes, Fload_module, string_suffixes_p)
(string_suffix_p, Fload, intern_c_string_1, defsubr)
(syms_of_lread): Add loading of external modules and the
docstrings of their functions.
* modules/curl: New module.
* modules/elisp: New module.
* modules/fmod: New module.
* modules/opaque: New module.
* modules/yaml: New module.
27 files changed: