fix unused parameter warnings in do_version() and show_usage()

This fixes:
  external/ethtool/ethtool.c:473:43: error: unused parameter 'ctx' [-Werror,-Wunused-parameter]
  static int do_version(struct cmd_context *ctx)

  external/ethtool/ethtool.c:5392:43: error: unused parameter 'ctx' [-Werror,-Wunused-parameter]
  static int show_usage(struct cmd_context *ctx)

Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I0cc52f33bb0e8d7627f5e84bb4e3dfa821d17cc8
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 4 insertions, 2 deletions

diff --git a/ethtool.c b/ethtool.c
index 082e37f..5e0deda 100644
--- a/ethtool.c
+++ b/ethtool.c
@@ -470,7 +470,7 @@ static int rxflow_str_to_type(const char *str)
 	return flow_type;
 }
 
-static int do_version(struct cmd_context *ctx)
+static int do_version(struct cmd_context *ctx maybe_unused)
 {
 	fprintf(stdout,
 		PACKAGE " version " VERSION
@@ -5484,7 +5484,7 @@ static const struct option {
 	{}
 };
 
-static int show_usage(struct cmd_context *ctx)
+static int show_usage(struct cmd_context *ctx maybe_unused)
 {
 	int i;
 
diff --git a/internal.h b/internal.h
index aecf1ce..ff52c6e 100644
--- a/internal.h
+++ b/internal.h
@@ -23,6 +23,8 @@
 #include <sys/ioctl.h>
 #include <net/if.h>
 
+#define maybe_unused __attribute__((__unused__))
+
 /* ethtool.h expects these to be defined by <linux/types.h> */
 #ifndef HAVE_BE_TYPES
 typedef uint16_t __be16;