Add automatic generation of headers

- The 'stripdecls.py' script replaces declarations in all headers by includes to
  generated headers.
  `ag '#\s*if(?!ndef NEOVIM_).*((?!#\s*endif).*\n)*#ifdef INCLUDE_GENERATED'`
  was used for this.
- Add and integrate gendeclarations.lua into the build system to generate the
  required includes.
- Add -Wno-unused-function
- Made a bunch of old-style definitions ANSI

This adds a requirement: all type and structure definitions must be present
before INCLUDE_GENERATED_DECLARATIONS-protected include.

Warning: mch_expandpath (path.h.generated.h) was moved manually. So far it is
the only exception.

src/nvim/ex_cmds2.h

@@ -1,95 +1,11 @@
 #ifndef NVIM_EX_CMDS2_H
 #define NVIM_EX_CMDS2_H
-/* ex_cmds2.c */
-void do_debug(char_u *cmd);
-void ex_debug(exarg_T *eap);
-void dbg_check_breakpoint(exarg_T *eap);
-int dbg_check_skipped(exarg_T *eap);
-void ex_breakadd(exarg_T *eap);
-void ex_debuggreedy(exarg_T *eap);
-void ex_breakdel(exarg_T *eap);
-void ex_breaklist(exarg_T *eap);
-linenr_T dbg_find_breakpoint(int file, char_u *fname, linenr_T after);
-int has_profiling(int file, char_u *fname, int *fp);
-void dbg_breakpoint(char_u *name, linenr_T lnum);
-void profile_start(proftime_T *tm);
-void profile_end(proftime_T *tm);
-void profile_sub(proftime_T *tm, proftime_T *tm2);
-char *profile_msg(proftime_T *tm);
-void profile_setlimit(long msec, proftime_T *tm);
-int profile_passed_limit(proftime_T *tm);
-void profile_zero(proftime_T *tm);
-void profile_divide(proftime_T *tm, int count, proftime_T *tm2);
-void profile_add(proftime_T *tm, proftime_T *tm2);
-void profile_self(proftime_T *self, proftime_T *total,
-                  proftime_T *children);
-void profile_get_wait(proftime_T *tm);
-void profile_sub_wait(proftime_T *tm, proftime_T *tma);
-int profile_equal(proftime_T *tm1, proftime_T *tm2);
-int profile_cmp(const proftime_T *tm1, const proftime_T *tm2);
-void ex_profile(exarg_T *eap);
-char_u *get_profile_name(expand_T *xp, int idx);
-void set_context_in_profile_cmd(expand_T *xp, char_u *arg);
-void profile_dump(void);
-void script_prof_save(proftime_T *tm);
-void script_prof_restore(proftime_T *tm);
-void prof_inchar_enter(void);
-void prof_inchar_exit(void);
-int prof_def_func(void);
-int autowrite(buf_T *buf, int forceit);
-void autowrite_all(void);
-int check_changed(buf_T *buf, int flags);
-void dialog_changed(buf_T *buf, int checkall);
-int can_abandon(buf_T *buf, int forceit);
-int check_changed_any(int hidden);
-int check_fname(void);
-int buf_write_all(buf_T *buf, int forceit);
-void get_arglist(garray_T *gap, char_u *str);
-int get_arglist_exp(char_u *str, int *fcountp, char_u ***fnamesp,
-                    int wig);
-void check_arg_idx(win_T *win);
-void ex_args(exarg_T *eap);
-void ex_previous(exarg_T *eap);
-void ex_rewind(exarg_T *eap);
-void ex_last(exarg_T *eap);
-void ex_argument(exarg_T *eap);
-void do_argfile(exarg_T *eap, int argn);
-void ex_next(exarg_T *eap);
-void ex_argedit(exarg_T *eap);
-void ex_argadd(exarg_T *eap);
-void ex_argdelete(exarg_T *eap);
-void ex_listdo(exarg_T *eap);
-void ex_compiler(exarg_T *eap);
-void ex_runtime(exarg_T *eap);
-int source_runtime(char_u *name, int all);
-int do_in_runtimepath(char_u *name, int all,
-                      void (*callback)(char_u *fname, void *ck),
-                      void *cookie);
-void ex_options(exarg_T *eap);
-void ex_source(exarg_T *eap);
-linenr_T *source_breakpoint(void *cookie);
-int *source_dbg_tick(void *cookie);
-int source_level(void *cookie);
-int do_source(char_u *fname, int check_other, int is_vimrc);
-void ex_scriptnames(exarg_T *eap);
-void scriptnames_slash_adjust(void);
-char_u *get_scriptname(scid_T id);
-void free_scriptnames(void);
-char *fgets_cr(char *s, int n, FILE *stream);
-char_u *getsourceline(int c, void *cookie, int indent);
-void script_line_start(void);
-void script_line_exec(void);
-void script_line_end(void);
-void ex_scriptencoding(exarg_T *eap);
-void ex_finish(exarg_T *eap);
-void do_finish(exarg_T *eap, int reanimate);
-int source_finished(char_u *(*fgetline)(int, void *, int), void *cookie);
-void ex_checktime(exarg_T *eap);
-char_u *get_mess_lang(void);
-void set_lang_var(void);
-void ex_language(exarg_T *eap);
-void free_locales(void);
-char_u *get_lang_arg(expand_T *xp, int idx);
-char_u *get_locales(expand_T *xp, int idx);
 
-#endif /* NVIM_EX_CMDS2_H */
+#include "nvim/ex_docmd.h"
+
+typedef void (*DoInRuntimepathCB)(char_u *, void *);
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "ex_cmds2.h.generated.h"
+#endif
+#endif  // NVIM_EX_CMDS2_H