mmtty: fix printing logs with --verbose

The _mm_log() implementation provided in 'mm-log-test.h' relies on
g_test_verbose() to decide whether the logs are printed or not. We are
not running under the GTest setup in mmtty, so that would not work
properly.

Just provide a custom _mm_log() method that checks for the
verbose_flag instead.

test/mmtty.c

@@ -23,7 +23,7 @@
 #include <glib.h>
 #include <gio/gio.h>
 
-#include <mm-log-test.h>
+#include <mm-log.h>
 #include <mm-port-serial.h>
 #include <mm-port-serial-at.h>
 #include <mm-serial-parsers.h>
@@ -242,6 +242,45 @@ start_cb (void)
     return G_SOURCE_REMOVE;
 }
 
+void
+_mm_log (gpointer     obj,
+         const gchar *module,
+         const gchar *loc,
+         const gchar *func,
+         guint32      level,
+         const gchar *fmt,
+         ...)
+{
+    va_list           args;
+    g_autofree gchar *msg = NULL;
+    const gchar      *level_str = NULL;
+
+    if (!verbose_flag)
+        return;
+
+    switch (level) {
+    case MM_LOG_LEVEL_DEBUG:
+        level_str = "debug";
+        break;
+    case MM_LOG_LEVEL_WARN:
+        level_str = "warning";
+        break;
+    case MM_LOG_LEVEL_INFO:
+        level_str = "info";
+        break;
+    case MM_LOG_LEVEL_ERR:
+        level_str = "error";
+        break;
+    default:
+        break;
+    }
+
+    va_start (args, fmt);
+    msg = g_strdup_vprintf (fmt, args);
+    va_end (args);
+    g_print ("[%s] %s\n", level_str ? level_str : "unknown", msg);
+}
+
 int main (int argc, char **argv)
 {
     GOptionContext *context;