Build fixes for -Og

Build fixes for -Og

Cleaning... 18 files.
[35/69] Compiling C object example/passthrough_ll.p/passthrough_ll.c.o
../example/passthrough_ll.c: In function ‘lo_opendir’:
../example/passthrough_ll.c:666:20: warning: ‘fd’ may be used uninitialized [-Wmaybe-uninitialized]
  666 |                 if (fd != -1)
      |                    ^
../example/passthrough_ll.c:637:13: note: ‘fd’ was declared here
  637 |         int fd;
      |             ^~
[38/69] Compiling C object test/test_syscalls.p/test_syscalls.c.o
../test/test_syscalls.c: In function ‘test_seekdir’:
../test/test_syscalls.c:804:16: warning: ‘de’ may be used uninitialized [-Wmaybe-uninitialized]
  804 |         while (de)
      |                ^~
../test/test_syscalls.c:776:24: note: ‘de’ was declared here
  776 |         struct dirent *de;
      |                        ^~

These are actually valid.

Signed-off-by: Bernd Schubert <bschubert@ddn.com>