In file included from /usr/include/assert.h:35,
                 from functest__getpty.c:3:
/usr/include/features.h:413:4: warning: #warning _FORTIFY_SOURCE requires compiling with optimization (-O) [-Wcpp]
  413 | #  warning _FORTIFY_SOURCE requires compiling with optimization (-O)
      |    ^~~~~~~
functest__getpty.c: In function 'main':
functest__getpty.c:28:3: warning: assignment to 'char (*)()' from 'char' makes pointer from integer without a cast [-Wint-conversion]
   28 | f = _getpty ();
      |   ^
/usr/bin/ld: /tmp/ccxqwvhe.o: in function `main':
functest__getpty.c:(.text+0xa): undefined reference to `_getpty'
collect2: error: ld returned 1 exit status