Add loadable modules using Daniel Colascione's ideas.scratch/dynamic-modules-2

See https://lists.gnu.org/archive/html/emacs-devel/2015-02/msg00960.html

* src/Makefile.in (base_obj): add module.o
  (LIBES): add -lltdl

* src/emacs.c (main): add syms_of_module

* src/lisp.h: add syms_of_module

* src/emacs_module.h: New file; emacs API for modules.

* src/module.c: New file; implement API.

* modules/basic/Makefile: New file; build example module on Linux.

* modules/basic/basic.c: New file; simple example module.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/lisp.h b/src/lisp.h
index 198f116fe02..577105bf322 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -4050,6 +4050,8 @@ Lisp_Object backtrace_top_function (void);
 extern bool let_shadows_buffer_binding_p (struct Lisp_Symbol *symbol);
 extern bool let_shadows_global_binding_p (Lisp_Object symbol);
 
+/* Defined in module.c.  */
+void syms_of_module (void);
 
 /* Defined in editfns.c.  */
 extern void insert1 (Lisp_Object);