Fix conflict on UNUSED() macro from OpenJDK 7

The OpenJDK 7 recently introduced the UNUSED() macro in their jni_md.h
header file, which is included from <jni.h>.  This causes a
compile-error if "constants.h", which defines our own UNUSED() macro, is
included as well as <jni.h>.

The OpenJDK UNUSED() macro is unsuitable for our own use, because it
prefixes the unused identifier with "UNUSED_" whereas we depend on the
parameter name remaining unchanged.

I have reported this as a Request for Enhancement with Oracle Java,
asking them to remove the UNUSED() macro, since it is not used by any
JNI or Java extension header files.  Review ID: JI-9013689.

In the meantime, constants.h now undefines UNUSED before defining it, so
including <jni.h> before "constants.h" will avoid a compile error.

cli.c

@@ -19,6 +19,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
 #include <stdio.h>
 #include <assert.h>
+#include "cli.h"
 #include "constants.h"
 #include "serval_types.h"
 #include "rhizome_types.h"
@@ -28,7 +29,6 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "str.h"
 #include "strbuf_helpers.h"
 #include "dataformats.h"
-#include "cli.h"
 
 int cli_usage(const struct cli_schema *commands, XPRINTF xpf)
 {

cli.h

@@ -20,13 +20,12 @@
 #ifndef __SERVAL_DNA__CLI_H
 #define __SERVAL_DNA__CLI_H
 
-#include "xprintf.h"
-#include "log.h"
 #include <stdint.h>
-
 #ifdef HAVE_JNI_H
 #include <jni.h>
 #endif
+#include "xprintf.h"
+#include "log.h"
 
 #define COMMAND_LINE_MAX_LABELS   (32)
 

constants.h

@@ -25,11 +25,19 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 // Number of elements in an array (Warning: does not work if A is a pointer!).
 #define NELS(A) (sizeof (A) / sizeof *(A))
 
+// Stop OpenJDK 7 from foisting their UNUSED() macro on us in <jni_md.h>
+#ifdef UNUSED
+# undef UNUSED
+#endif
+
 // To suppress the "unused parameter" warning from -Wunused-parameter.
-#ifdef __GNUC__
-#  define UNUSED(x) x __attribute__((__unused__))
+#ifndef __has_attribute
+  #define __has_attribute(x) 0
+#endif
+#if (defined(__GNUC__)) || __has_attribute(unused)
+  #define UNUSED(x) x __attribute__((__unused__))
 #else
-#  define UNUSED(x) x
+  #define UNUSED(x) x
 #endif
 
 // UDP Port numbers for various Serval services.

directory_service.c

@@ -23,8 +23,8 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include <stdio.h>
 #include <unistd.h>
 #include <inttypes.h>
-#include "constants.h"
 #include "serval.h"
+#include "constants.h"
 #include "mdp_client.h"
 #include "str.h"
 

dna_helper.c

@@ -52,13 +52,13 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include <sys/stat.h>
 #include <signal.h>
 #include "sighandlers.h"
+#include "serval.h"
 #include "conf.h"
 #include "str.h"
 #include "strbuf.h"
 #include "strbuf_helpers.h"
 #include "dataformats.h"
 #include "overlay_address.h"
-#include "serval.h"
 
 /*
   The challenge with making an interface for calling an external program to 

keyring.c

@@ -20,13 +20,10 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
 #include <stdio.h>
 #include <assert.h>
-#include "constants.h"
 #include "serval.h"
-#include "str.h"
-#include "mem.h"
-#include "rotbuf.h"
-#include "conf.h"
 #include "rhizome.h"
+#include "conf.h"
+#include "constants.h"
 #include "nacl.h"
 #include "overlay_address.h"
 #include "crypto.h"
@@ -35,6 +32,9 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "overlay_buffer.h"
 #include "keyring.h"
 #include "dataformats.h"
+#include "str.h"
+#include "mem.h"
+#include "rotbuf.h"
 
 static void keyring_free_keypair(keypair *kp);
 static void keyring_free_context(keyring_context *c);

meshms_restful.c

@@ -17,8 +17,8 @@ along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
 
-#include "conf.h"
 #include "serval.h"
+#include "conf.h"
 #include "httpd.h"
 #include "strbuf_helpers.h"
 

msp_proxy.c

@@ -18,11 +18,11 @@
  */
 
 #include <signal.h>
+#include "cli.h"
 #include "serval_types.h"
 #include "mdp_client.h"
 #include "msp_client.h"
 #include "fdqueue.h"
-#include "cli.h"
 #include "log.h"
 #include "mem.h"
 #include "str.h"

nonce.c

@@ -17,9 +17,9 @@ along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
 
+#include "cli.h"
 #include "constants.h"
 #include "os.h"
-#include "cli.h"
 
 int nonce_initialised=0;
 unsigned char nonce_buffer[128];

rhizome_http.c

@@ -17,8 +17,8 @@ along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
 
-#include "conf.h"
 #include "serval.h"
+#include "conf.h"
 #include "httpd.h"
 #include "str.h"
 #include "strbuf.h"

rhizome_restful.c

@@ -17,8 +17,8 @@ along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
 
-#include "conf.h"
 #include "serval.h"
+#include "conf.h"
 #include "httpd.h"
 #include "strbuf_helpers.h"
 

serval.h

@@ -117,11 +117,11 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include <fcntl.h>
 #include <sys/stat.h>
 
+#include "cli.h"
 #include "serval_types.h"
 #include "sighandlers.h"
 #include "instance.h"
 #include "fdqueue.h"
-#include "cli.h"
 #include "constants.h"
 #include "mem.h"
 #include "xprintf.h"

simulator.c

@@ -24,15 +24,15 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include <time.h>
 #include <sys/time.h>
 
+#include "console.h"
+#include "conf.h"
 #include "mem.h"
 #include "socket.h"
 #include "fdqueue.h"
 #include "str.h"
 #include "strbuf.h"
 #include "strbuf_helpers.h"
-#include "conf.h"
 #include "net.h"
-#include "console.h"
 #include "limit.h"
 
 #define MTU 1600