Fix mg_time on mbed and make DNS work around epoch

PUBLISHED_FROM=c1aeef9dc25baba794b3269b44441c5bafbca5a8

v7.c

@@ -838,10 +838,55 @@ int inet_pton(int af, const char *src, void *dst);
 
 /* Amalgamated: #include "mbed.h" */
 
+#include <assert.h>
+#include <ctype.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <stdint.h>
+#include <string.h>
+#include <time.h>
+
 #ifndef CS_ENABLE_STDIO
 #define CS_ENABLE_STDIO 1
 #endif
 
+/*
+ * mbed can be compiled with the ARM compiler which
+ * just doesn't come with a gettimeofday shim
+ * because it's a BSD API and ARM targets embedded
+ * non-unix platforms.
+ */
+#if defined(__ARMCC_VERSION) || defined(__ICCARM__)
+#define _TIMEVAL_DEFINED
+#define gettimeofday _gettimeofday
+
+/* copied from GCC on ARM; for some reason useconds are signed */
+typedef long suseconds_t; /* microseconds (signed) */
+struct timeval {
+  time_t tv_sec;       /* seconds */
+  suseconds_t tv_usec; /* and microseconds */
+};
+
+#endif
+
+#if MG_NET_IF == MG_NET_IF_SIMPLELINK
+
+typedef int sock_t;
+#define INVALID_SOCKET (-1)
+
+#define to64(x) strtoll(x, NULL, 10)
+#define INT64_FMT PRId64
+#define INT64_X_FMT PRIx64
+#define SIZE_T_FMT "u"
+
+#define SOMAXCONN 8
+
+const char *inet_ntop(int af, const void *src, char *dst, socklen_t size);
+char *inet_ntoa(struct in_addr in);
+int inet_pton(int af, const char *src, void *dst);
+
+#endif /* MG_NET_IF == MG_NET_IF_SIMPLELINK */
+
 #endif /* CS_PLATFORM == CS_P_MBED */
 #endif /* CS_COMMON_PLATFORMS_PLATFORM_MBED_H_ */
 #ifdef V7_MODULE_LINES
@@ -11074,6 +11119,22 @@ void cr_context_free(struct cr_ctx *p_ctx) {
 
 long timezone;
 
+/*
+ * The GCC ARM toolchain for implements a weak
+ * gettimeofday stub that should be implemented
+ * to hook the OS time source. But mbed OS doesn't do it;
+ * the mbed doc only talks about C date and time functions:
+ *
+ * https://docs.mbed.com/docs/mbed-os-api-reference/en/5.1/APIs/tasks/Time/
+ *
+ * gettimeof day is a BSD API.
+ */
+int _gettimeofday(struct timeval *tv, void *tzvp) {
+  tv->tv_sec = time(NULL);
+  tv->tv_usec = 0;
+  return 0;
+}
+
 #endif /* CS_PLATFORM == CS_P_MBED */
 #ifdef V7_MODULE_LINES
 #line 1 "v7/builtin/file.c"