Programs/pgmprivs_linux.c: fix build with gcc < 5
Programs/pgmprivs_linux.c: fix build with gcc < 5

Build with gcc < 5 is broken since version 6.2 and
https://github.com/brltty/brltty/commit/8ce262f2c15f10a40d9cbae0b3c88b466970a055:

./pgmprivs_linux.c: In function 'getPrivilegeParameterNames':
./pgmprivs_linux.c:2220:3: error: array initialized from non-constant array expression
   static const char *const names[] = NULL_TERMINATED_STRING_ARRAY(
   ^

Build was partially fixed since
https://github.com/brltty/brltty/commit/8ae78dd560d00c5074158f90be5ac8dac80183db
but it forgot to update pgmprivs_linux.c

Fixes:
 - http://autobuild.buildroot.org/results/58afeb50a0ecdb8b527d7c9946bcae290b79b055

Signed-off-by: Fabrice Fontaine <7d88633730b8b85c1516e612893df72eae9cd341@gmail.com>

brltty/brltty,brltty/brltty,brltty/brltty,brltty/brltty,brltty/brltty,brltty/brltty