include: Add macro for unused arguments and variables

Signed-off-by: Andreas Schneider <asn@cryptomilk.org>

ConfigureChecks.cmake

@@ -343,6 +343,26 @@ int main(void) {
     return 0;
 }" HAVE_FALLTHROUGH_ATTRIBUTE)
 
+check_c_source_compiles("
+#define __unused __attribute__((unused))
+
+static int do_nothing(int i __unused)
+{
+    return 0;
+}
+
+int main(void)
+{
+    int i;
+
+    i = do_nothing(5);
+    if (i > 5) {
+        return 1;
+    }
+
+    return 0;
+}" HAVE_UNUSED_ATTRIBUTE)
+
 check_c_source_compiles("
 #include <string.h>
 

config.h.cmake

@@ -213,6 +213,7 @@
 #cmakedefine HAVE_MSC_THREAD_LOCAL_STORAGE 1
 
 #cmakedefine HAVE_FALLTHROUGH_ATTRIBUTE 1
+#cmakedefine HAVE_UNUSED_ATTRIBUTE 1
 
 #cmakedefine HAVE_CONSTRUCTOR_ATTRIBUTE 1
 #cmakedefine HAVE_DESTRUCTOR_ATTRIBUTE 1

include/libssh/priv.h

@@ -302,8 +302,6 @@ int ssh_connector_remove_event(ssh_connector connector);
 void explicit_bzero(void *s, size_t n);
 #endif /* !HAVE_EXPLICIT_BZERO */
 
-#define UNUSED(x) (void)(x)
-
 /**
  * This is a hack to fix warnings. The idea is to use this everywhere that we
  * get the "discarding const" warning by the compiler. That doesn't actually
@@ -388,6 +386,22 @@ void explicit_bzero(void *s, size_t n);
 # endif /* HAVE_FALLTHROUGH_ATTRIBUTE */
 #endif /* FALL_THROUGH */
 
+#ifndef __unused__
+# ifdef HAVE_UNUSED_ATTRIBUTE
+#  define __unused__ __attribute__((unused))
+# else /* HAVE_UNUSED_ATTRIBUTE */
+#  define __unused__
+# endif /* HAVE_UNUSED_ATTRIBUTE */
+#endif /* __unused__ */
+
+#ifndef UNUSED_PARAM
+#define UNUSED_PARAM(param) param __unused__
+#endif /* UNUSED_PARAM */
+
+#ifndef UNUSED_VAR
+#define UNUSED_VAR(var) __unused__ var
+#endif /* UNUSED_VAR */
+
 void ssh_agent_state_free(void *data);
 
 #endif /* _LIBSSH_PRIV_H */

src/pki_crypto.c

@@ -1038,7 +1038,7 @@ int pki_privkey_build_rsa(ssh_key key,
                           ssh_string n,
                           ssh_string e,
                           ssh_string d,
-                          ssh_string iqmp,
+                          UNUSED_PARAM(ssh_string iqmp),
                           ssh_string p,
                           ssh_string q)
 {
@@ -1053,7 +1053,6 @@ int pki_privkey_build_rsa(ssh_key key,
     bn = ssh_make_string_bn(n);
     be = ssh_make_string_bn(e);
     bd = ssh_make_string_bn(d);
-    UNUSED(iqmp);
     /*biqmp = ssh_make_string_bn(iqmp);*/
     bp = ssh_make_string_bn(p);
     bq = ssh_make_string_bn(q);