mail/dbmail: Remove dead sbrk linkage

Differential Revision:	https://reviews.freebsd.org/D42973

mail/dbmail/Makefile

@@ -1,5 +1,6 @@
 PORTNAME=	dbmail
 PORTVERSION=	3.4.1
+PORTREVISION=	1
 DISTVERSIONPREFIX=	v
 CATEGORIES=	mail
 
@@ -9,8 +10,6 @@ WWW=		http://www.dbmail.org/
 
 LICENSE=	GPLv2
 
-BROKEN_aarch64=	Fails to link: missing sbrk
-
 BUILD_DEPENDS=	asciidoc:textproc/asciidoc \
 		docbook-sgml>0:textproc/docbook-sgml \
 		xmlto:textproc/xmlto

mail/dbmail/files/patch-src_mpool_mpool.c

@@ -0,0 +1,38 @@
+--- src/mpool/mpool.c.orig
++++ src/mpool/mpool.c
+@@ -241,6 +241,7 @@
+   (void)printf("allocating %u pages or %lu bytes\n", page_n, size);
+ #endif
+   
++#if 0
+   if (BIT_IS_SET(mp_p->mp_flags, MPOOL_FLAG_USE_SBRK)) {
+     mem = sbrk(size);
+     if (mem == (void *)-1) {
+@@ -263,7 +264,9 @@
+       mem = (char *)mem + fill;
+     }
+   }
+-  else {
++  else
++#endif
++  {
+     state = MAP_PRIVATE;
+ #ifdef MAP_FILE
+     state |= MAP_FILE;
+@@ -937,12 +940,15 @@
+     }
+   }
+   
++#if 0
+   if (BIT_IS_SET(flags, MPOOL_FLAG_USE_SBRK)) {
+     mp.mp_fd = -1;
+     mp.mp_addr = NULL;
+     mp.mp_top = 0;
+   }
+-  else {
++  else
++#endif
++  {
+     /* open dev-zero for our mmaping */
+     mp.mp_fd = open("/dev/zero", O_RDWR, 0);
+     if (mp.mp_fd < 0) {