tests/mock_*.c: Mark unused function arguments as such.

 This resolves:

 mock_pam.c: In function 'fake_conv':
 mock_pam.c:22:20: error: unused parameter 'num_msg' [-Werror=unused-parameter]
    22 | int fake_conv (int num_msg, const struct pam_message **msg,
       |                ~~~~^~~~~~~
 mock_pam.c:23:39: error: unused parameter 'appdata_ptr' [-Werror=unused-parameter]
    23 |     struct pam_response **resp, void *appdata_ptr)
       |                                 ~~~~~~^~~~~~~~~~~
 mock_pam.c: In function 'fake_conv_empty_password':
 mock_pam.c:51:35: error: unused parameter 'num_msg' [-Werror=unused-parameter]
    51 | int fake_conv_empty_password (int num_msg, const struct pam_message **msg,
       |                               ~~~~^~~~~~~
 mock_pam.c:52:39: error: unused parameter 'appdata_ptr' [-Werror=unused-parameter]
    52 |     struct pam_response **resp, void *appdata_ptr)
       |                                 ~~~~~~^~~~~~~~~~~
 cc1: all warnings being treated as errors

1 files changed, 14 insertions, 9 deletions

diff --git a/tests/mock_guest.c b/tests/mock_guest.c
index 7673995..218f30e 100644
--- a/tests/mock_guest.c
+++ b/tests/mock_guest.c
@@ -22,39 +22,44 @@ static struct passwd guest = { "guest",
 							   "/tmp",
 							   "/bin/true" };
 struct passwd *
-getpwnam (const char *username)
+getpwnam (const char __attribute__((unused)) *username)
 { return &guest; }
 
 int
-setgroups(size_t size, const gid_t *list)
+setgroups(size_t __attribute__((unused)) size,
+          const gid_t __attribute__((unused)) *list)
 {
 	errno = EPERM;
 	return -1;
 }
 
 int
-setgid(gid_t gid)
+setgid(gid_t __attribute__((unused)) gid)
 { return 0; }
 
 int
-setuid(uid_t uid)
+setuid(uid_t __attribute__((unused)) uid)
 { return 0; }
 
 int
-setegid(gid_t gid)
+setegid(gid_t __attribute__((unused)) gid)
 { return 0; }
 
 int
-seteuid(uid_t uid)
+seteuid(uid_t __attribute__((unused)) uid)
 { return 0; }
 
-int chmod(const char *path, mode_t mode)
+int chmod(const char __attribute__((unused)) *path,
+          mode_t __attribute__((unused)) mode)
 { return 0; }
 
-int chown(const char *path, uid_t owner, gid_t group)
+int chown(const char __attribute__((unused)) *path,
+          uid_t __attribute__((unused)) owner,
+          gid_t __attribute__((unused)) group)
 { return 0; }
 
-int execvp(const char *file, char *const argv[])
+int execvp(const char __attribute__((unused)) *file,
+           char __attribute__((unused)) *const argv[])
 {
 	return 0;
 }