cad/NASTRAN-95: Unbreak build with GCC 10

bufchk.f:16:28:

16 |      1                 '1'X    ,  '2'X     , '3'X    , '4'X  , '8'X   /
   |                            1

Error: BOZ constant at (1) uses nonstandard postfix syntax [see '-fno-allow-invalid-boz']
bufchk.f:18:32:

18 |      1                 'F1111'X,  'F2222'X , 'FAAAA'X, 'FBBBB'X /
   |                                1

Error: BOZ constant at (1) uses nonstandard postfix syntax [see '-fno-allow-invalid-boz']
bufchk.f:20:32:

20 |      1                 'F5555'X,  'F7777'X , 'F8888'X, 'F9999'X /
   |                                1

Error: BOZ constant at (1) uses nonstandard postfix syntax [see '-fno-allow-invalid-boz']

http://package18.nyi.freebsd.org/data/121amd64-default-PR244494/2020-06-10_18h04m44s/logs/errors/NASTRAN-95-20160908_6.log

PR: 246700