malloc.h hygiene

This attempts to future-proof Emacs a bit against possible glibc
changes, by having Emacs use <malloc.h> declarations rather than
coding them up by hand.  Problem noted by Florian Weimer in:
https://sourceware.org/ml/libc-alpha/2016-01/msg00777.html
Implement this mainly by moving malloc.h-related functions from
emacs.c (which does not include <malloc.h>) to alloc.c (which does).
* src/alloc.c (my_heap_start) [DOUG_LEA_MALLOC || GNU_LINUX]:
New function.
The remaining changes to this file apply only if DOUG_LEA_MALLOC.
(alloc_unexec_pre, alloc_unexec_post): New functions.
(malloc_initialize_hook): Use my_heap_start and alloc_unexec_post.
(__MALLOC_HOOK_VOLATILE): New macro, if not already defined.
(__malloc_initialize_hook): Use it.
(malloc_state_ptr, malloc_initialize_hook, __malloc_initialize_hook):
Move here from ...
* src/emacs.c: ... here.
(malloc_get_state, malloc_set_state): Remove extern decls.
(my_heap_start) [DOUG_LEA_MALLOC || GNU_LINUX]: Remove static var.
All uses changed to similarly-named new function.
(Fdump_emacs): Use new functions alloc_unexec_pre, alloc_unexec_post.
* src/lisp.h (my_heap_start, alloc_unexec_pre, alloc_unexec_post):
New decls.

1 files changed, 8 insertions, 0 deletions

diff --git a/src/lisp.h b/src/lisp.h
index 6be2104ef9e..82cbca8e6ba 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -3590,6 +3590,7 @@ extern void parse_str_as_multibyte (const unsigned char *, ptrdiff_t,
                                     ptrdiff_t *, ptrdiff_t *);
 
 /* Defined in alloc.c.  */
+extern void *my_heap_start (void);
 extern void check_pure_size (void);
 extern void free_misc (Lisp_Object);
 extern void allocate_string_data (struct Lisp_String *, EMACS_INT, EMACS_INT);
@@ -3601,6 +3602,13 @@ extern void mark_object (Lisp_Object);
 #if defined REL_ALLOC && !defined SYSTEM_MALLOC && !defined HYBRID_MALLOC
 extern void refill_memory_reserve (void);
 #endif
+#ifdef DOUG_LEA_MALLOC
+extern void alloc_unexec_pre (void);
+extern void alloc_unexec_post (void);
+#else
+INLINE void alloc_unexec_pre (void) {}
+INLINE void alloc_unexec_post (void) {}
+#endif
 extern const char *pending_malloc_warning;
 extern Lisp_Object zero_vector;
 extern Lisp_Object *stack_base;