Bug 1134123 - Disable (infinite) chunk recycling in jemalloc3. r=njn

Jemalloc 3 has, by default, a form of chunk recycling enabled, where it
actually doesn't unmap any chunk it ever allocated. Considering Gecko has
other uses of mmap, it can lead to premature address space exhaustion.

Until we have actual (limited) chunk recycling in jemalloc3 from bug
1107677, just disable this feature.

configure.in

@@ -9130,6 +9130,9 @@ if test -z "$MOZ_NATIVE_JEMALLOC" -a "$MOZ_MEMORY" && test -n "$MOZ_JEMALLOC3" -
   # Force disable DSS support in jemalloc.
   ac_configure_args="$ac_configure_args ac_cv_func_sbrk=false"
 
+  # Make Linux builds munmap freed chunks instead of recycling them.
+  ac_configure_args="$ac_configure_args --enable-munmap"
+
   if ! test -e memory/jemalloc; then
     mkdir -p memory/jemalloc
   fi