loader: ghlvl #204, Use __secure_getenv if secure_getenv is unavailable
loader: ghlvl #204, Use __secure_getenv if secure_getenv is unavailable

Also add group id check to getenv suid check in loader.

Change-Id: Icbc08258498f893ee5fce144c043bdc6bd8e5423

KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools