input/output test code is broken

[tthsqe12]

After c7272e0
compilation of fmpz/test/t-out_inp_raw.c gives warnings and then crashes.

    CC   ../build/fmpz/test/t-out_inp_raw
test/t-out_inp_raw.c: In function ‘main’:
test/t-out_inp_raw.c:71:19: warning: implicit declaration of function ‘fdopen’; did you mean ‘fopen’? [-Wimplicit-function-declaration]
   71 |             out = fdopen(fd[1], "w");
      |                   ^~~~~~
      |                   fopen
test/t-out_inp_raw.c:71:17: warning: assignment to ‘FILE *’ {aka ‘struct _IO_FILE *’} from ‘int’ makes pointer from integer without a cast [-Wint-conversion]
   71 |             out = fdopen(fd[1], "w");
      |                 ^
test/t-out_inp_raw.c:103:16: warning: assignment to ‘FILE *’ {aka ‘struct _IO_FILE *’} from ‘int’ makes pointer from integer without a cast [-Wint-conversion]
  103 |             in = fdopen(fd[0], "r");
      |                ^
out_raw/inp_raw....make[1]: *** [../Makefile.subdirs:97: ../build/fmpz/test/t-out_inp_raw_RUN] Segmentation fault (core dumped)

[wbhart]

Does the problem go away if that line is placed in fmpz.h?