Merge pull request #5 from cockroachdb/knz/freebsd-compat

Make c-jemalloc compile on FreeBSD.

Author: knz

cgo_flags.go

@@ -7,5 +7,6 @@ package jemalloc
 // #cgo linux CPPFLAGS: -D_GNU_SOURCE
 // #cgo darwin CFLAGS: -Idarwin_includes/internal/include -Idarwin_includes/internal/include/jemalloc/internal
 // #cgo linux CFLAGS: -Ilinux_includes/internal/include -Ilinux_includes/internal/include/jemalloc/internal
+// #cgo freebsd CFLAGS: -Ifreebsd_includes/internal/include -Ifreebsd_includes/internal/include/jemalloc/internal
 // #cgo LDFLAGS: -lm
 import "C"