ACPICA: OSL: Update environments to improve portability

This patch contains some environment updates that will be used by acpidump
because:
 1. The follow-up commits will release osunixxf.c to the Linux kernel for
    acpidump to link, and
 2. Such environment settings will be used to avoid linkage issues.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>