[Hurd, kFreeBSD] boehm-gc: Use mmap instead of brk

	boehm-gc/
	* configure.host: Set gc_use_mmap on *-kfreebsd-gnu* and *-gnu*.
	* include/private/gcconfig.h [HURD && USE_MMAP]: Define
	USE_MMAP_ANON.

From-SVN: r234534

boehm-gc/ChangeLog

+2016-03-29  Samuel Thibault  <samuel.thibault@ens-lyon.org>
+
+	* configure.host: Set gc_use_mmap on *-kfreebsd-gnu* and *-gnu*.
+	* include/private/gcconfig.h [HURD && USE_MMAP]: Define
+	USE_MMAP_ANON.
+
 2016-03-16  Andreas Schwab  <schwab@suse.de>
 
 	* include/private/gcconfig.h [AARCH64] (ALIGNMENT, CPP_WORDSZ):

boehm-gc/configure.host

@@ -41,7 +41,7 @@ else
 fi
 
 case "${host}" in
-  *-linux*)
+  *-linux*|*-kfreebsd-gnu*|*-gnu*)
     gc_use_mmap=yes
     ;;
 esac

boehm-gc/include/private/gcconfig.h

@@ -2137,7 +2137,7 @@
 #   endif
 # endif
 
-#if defined(LINUX) && defined(USE_MMAP)
+#if (defined(LINUX) || defined(HURD)) && defined(USE_MMAP)
     /* The kernel may do a somewhat better job merging mappings etc.	*/
     /* with anonymous mappings.						*/
 #   define USE_MMAP_ANON