Unexpected warning output

[baentsch]

Describe the bug
liboqs build should complete without error or warning output on supported platforms.

To Reproduce
run cmake -GNinja -B build -S . && cd build && ninja

Expected behavior
Correct build without error or warning output.

Screenshots
Actual output:

[1408/1442] Building C object tests/CMakeFiles/kat_sig_stfl.dir/kat_sig_stfl.c.o
/home/baentsch/git/oqs/liboqs/tests/kat_sig_stfl.c: In function ‘sig_stfl_kat’:
/home/baentsch/git/oqs/liboqs/tests/kat_sig_stfl.c:314:17: warning: ignoring return value of ‘fscanf’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  314 |                 fscanf(fp_rsp, "%llu", &sigs_remain);
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/baentsch/git/oqs/liboqs/tests/kat_sig_stfl.c:323:17: warning: ignoring return value of ‘fscanf’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  323 |                 fscanf(fp_rsp, "%llu", &sigs_maximum);
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[1442/1442] Linking C executable tests/dump_alg_info

Environment (please complete the following information):

• OS: [Ubuntu 22]
• OpenSSL version [3.0.2]
• Compiler version used [gcc 11.4]
• Build variables used [None -- see command above]
• liboqs version [main branch]

Tagging @cothan @ashman-p as this might be related to missing STFL guards/#defines.