$ make
cc -Wall -fPIC -ansi -pedantic   -c -o pam_oauth2.o pam_oauth2.c
pam_oauth2.c: In function ‘pam_sm_authenticate’:
pam_oauth2.c:195:12: warning: ISO C90 forbids variable length array ‘ct’ [-Wvla]
  195 |     struct check_tokens ct[argc];
      |            ^~~~~~~~~~~~
cc -shared pam_oauth2.o -lcurl -o pam_oauth2.so