Fix warnings reported by -Wpedantic

Previously CI hasn't been running with -Wpedantic (using autoconf), so
these haven't been reported previously.

- replace BUILD_ASSERT with static_assert()
- don't use %m GNU extension for printf
- don't use arithmetic on void*
- remove unused variables

Change-Id: I97d1acc908f06773b8b1ee95bfee80760fdc7a63
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
diff --git a/core.c b/core.c
index cc39dcf..33f5093 100644
--- a/core.c
+++ b/core.c
@@ -72,13 +72,6 @@
 	size_t max_message_size;
 };
 
-#ifndef BUILD_ASSERT
-#define BUILD_ASSERT(x)                                                        \
-	do {                                                                   \
-		(void)sizeof(char[0 - (!(x))]);                                \
-	} while (0)
-#endif
-
 #ifndef ARRAY_SIZE
 #define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
 #endif
@@ -317,7 +310,7 @@
 	size_t i;
 
 	/* Cleanup message assembly contexts */
-	BUILD_ASSERT(ARRAY_SIZE(mctp->msg_ctxs) < SIZE_MAX);
+	static_assert(ARRAY_SIZE(mctp->msg_ctxs) < SIZE_MAX, "size");
 	for (i = 0; i < ARRAY_SIZE(mctp->msg_ctxs); i++) {
 		struct mctp_msg_ctx *tmp = &mctp->msg_ctxs[i];
 		if (tmp->buf)
@@ -439,8 +432,11 @@
 
 static inline bool mctp_ctrl_cmd_is_transport(struct mctp_ctrl_msg_hdr *hdr)
 {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wtype-limits"
 	return ((hdr->command_code >= MCTP_CTRL_CMD_FIRST_TRANSPORT) &&
 		(hdr->command_code <= MCTP_CTRL_CMD_LAST_TRANSPORT));
+#pragma GCC diagnostic pop
 }
 
 static bool mctp_ctrl_handle_msg(struct mctp_bus *bus, mctp_eid_t src,