LU-12511 build: make fscrypt detection work for native client

LU-12511 build: make fscrypt detection work for native client

The current code when built against the native client fails to
detect fscrypt so no support is built into the tools. This
patch makes the LC_FSCRUPT_SUPPORT test against the fscrypt UAPI
header to see if its at a level we can support natively.

Test-Parameters: trivial
Change-Id: Ic65f9dca637edd9194acbcf90e02da9681b26ab0
Signed-off-by: James Simmons <jsimmons@infradead.org>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/58949
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Timothy Day <timday@amazon.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>