>From f65fff5bb5f2f2eee3b258538f1abb70eeb911c6 Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@libc.org>
Date: Sun, 22 Feb 2015 04:25:03 +0100
Subject: [PATCH 4/5] Add musl patch to support HYBRID_MALLOC on elf systems.

* src/unexelf.c (unexec): Define bss_sbrk_did_unexec.
* src/gmalloc.c: Adjust for HYBRID_MALLOC in the non CYGWIN case.
(__default_morecore): Here, in particular.

* configure.ac: Define HYBRID_MALLOC when unexelf.o is used.
New variable SHEAP_OBJ.
* src/Makefile.in: Use it.

Except for build system fixes this is essentially the same as

http://git.alpinelinux.org/cgit/aports/tree/testing/emacs/musl.patch?id=d6f211ec868df4657c745b8ba2bae77b2a7fb7f6

The original patch contains one unrelated hunk, which will be
committed separately.
---
 configure.ac    | 12 ++++++++++--
 src/Makefile.in |  6 +++++-
 src/gmalloc.c   |  4 ++--
 src/unexelf.c   |  5 +++++
 4 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/configure.ac b/configure.ac
index 63e354e..56e2f12 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2117,7 +2117,13 @@ case "$opsys" in
   cygwin) hybrid_malloc=yes;;
 esac
 
+if test "${system_malloc}" != yes && test "${doug_lea_malloc}" != yes \
+   && test "${UNEXEC_OBJ}" = unexelf.o && test "${hybrid_malloc}" != no; then
+  hybrid_malloc=yes
+fi
+
 GMALLOC_OBJ=
+SHEAP_OBJ=
 if test "${system_malloc}" = "yes"; then
   AC_DEFINE([SYSTEM_MALLOC], 1,
     [Define to 1 to use the system memory allocator, even if it is not
@@ -2132,6 +2138,7 @@ elif test "$hybrid_malloc" = yes; then
   GNU_MALLOC=
   GNU_MALLOC_reason="only before dumping"
   GMALLOC_OBJ=gmalloc.o
+  SHEAP_OBJ=sheap.o
   VMLIMIT_OBJ=
 else
   test "$doug_lea_malloc" != "yes" && GMALLOC_OBJ=gmalloc.o
@@ -2152,9 +2159,10 @@ else
   fi
 fi
 AC_SUBST(GMALLOC_OBJ)
+AC_SUBST(SHEAP_OBJ)
 AC_SUBST(VMLIMIT_OBJ)
 
-if test "$doug_lea_malloc" = "yes" ; then
+if test "$doug_lea_malloc" = "yes" && test "$hybrid_malloc" != yes; then
   if test "$GNU_MALLOC" = yes ; then
     GNU_MALLOC_reason="
       (Using Doug Lea's new malloc from the GNU C Library.)"
@@ -4970,7 +4978,7 @@ fi
 AC_SUBST(RALLOC_OBJ)
 
 if test "$opsys" = "cygwin"; then
-  CYGWIN_OBJ="sheap.o cygw32.o"
+  CYGWIN_OBJ="cygw32.o"
   ## Cygwin differs because of its unexec().
   PRE_ALLOC_OBJ=
   POST_ALLOC_OBJ=lastfile.o
diff --git a/src/Makefile.in b/src/Makefile.in
index f1d780f..ece8858 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -243,7 +243,10 @@ XFIXES_CFLAGS = @XFIXES_CFLAGS@
 ## widget.o if USE_X_TOOLKIT, otherwise empty.
 WIDGET_OBJ=@WIDGET_OBJ@
 
-## sheap.o if CYGWIN, otherwise empty.
+## sheap.o if HYBRID_MALLOC, otherwise empty.
+SHEAP_OBJ=@SHEAP_OBJ@
+
+## cygw32.o if CYGWIN, otherwise empty.
 CYGWIN_OBJ=@CYGWIN_OBJ@
 
 ## fontset.o fringe.o image.o if we have any window system
@@ -384,6 +387,7 @@ base_obj = dispnew.o frame.o scroll.o xdisp.o menu.o $(XMENU_OBJ) window.o \
 	region-cache.o sound.o atimer.o \
 	doprnt.o intervals.o textprop.o composite.o xml.o $(NOTIFY_OBJ) \
 	profiler.o decompress.o \
+	$(SHEAP_OBJ) \
 	$(MSDOS_OBJ) $(MSDOS_X_OBJ) $(NS_OBJ) $(CYGWIN_OBJ) $(FONT_OBJ) \
 	$(W32_OBJ) $(WINDOW_SYSTEM_OBJ) $(XGSELOBJ)
 obj = $(base_obj) $(NS_OBJC_OBJ)
diff --git a/src/gmalloc.c b/src/gmalloc.c
index 240408e..530b3b2 100644
--- a/src/gmalloc.c
+++ b/src/gmalloc.c
@@ -70,7 +70,7 @@ extern void emacs_abort (void);
 #define aligned_alloc galigned_alloc
 #define free gfree
 
-#ifdef CYGWIN
+#ifdef HYBRID_MALLOC
 extern void *bss_sbrk (ptrdiff_t size);
 extern int bss_sbrk_did_unexec;
 extern char bss_sbrk_buffer[];
@@ -1542,7 +1542,7 @@ void *
 __default_morecore (ptrdiff_t increment)
 {
   void *result;
-#if defined (CYGWIN)
+#ifdef HYBRID_MALLOC
   if (!DUMPED)
     {
       return bss_sbrk (increment);
diff --git a/src/unexelf.c b/src/unexelf.c
index c10c7f2..3d10aa0 100644
--- a/src/unexelf.c
+++ b/src/unexelf.c
@@ -227,6 +227,11 @@ unexec (const char *new_name, const char *old_name)
   off_t new_file_size;
   void *new_break;
 
+#ifdef HYBRID_MALLOC
+  extern int bss_sbrk_did_unexec;
+  bss_sbrk_did_unexec = 1;
+#endif
+
   /* Pointers to the base of the image of the two files.  */
   caddr_t old_base, new_base;
 
-- 
2.6.3