bsd-user: move strace OS/arch dependent code to host/arch dirs

This change moves host OS and arch dependent code for the sysarch
system call related to the -strace functionality into the
appropriate host OS and target arch directories.

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Sean Bruno <sburno@FreeBSD.org>
[ imp integrated minor build fixes from sbruno ]
Signed-off-by: Warner Losh <imp@FreeBSD.org>
Message-Id: <20201218205451.10559-4-imp@freebsd.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
diff --git a/meson.build b/meson.build
index 563688d..e4db67c 100644
--- a/meson.build
+++ b/meson.build
@@ -2047,6 +2047,7 @@
       target_inc += include_directories('linux-user/host/' / config_host['ARCH'])
     else
       base_dir = 'bsd-user'
+      target_inc += include_directories('bsd-user/freebsd')
     endif
     target_inc += include_directories(
       base_dir,