Fix mismatching declarations so build does not fail with -Werror=lto-type-mismatch

Bug: https://bugs.gentoo.org/855017

This patch is already merged upstream, see: https://github.com/folkertvanheusden/multitail/pull/10

Signed-off-by: Pascal Jäger <pascal.jaeger@leimstift.de>

--- a/globals.c
+++ b/globals.c
@@ -81,7 +81,7 @@ double heartbeat_t = 0.0;
 off64_t msf_prev_size = 0;

 dtime_t msf_last_check = 0;
-dtime_t mt_started;
+time_t mt_started;

 pid_t children_list[MAX_N_SPAWNED_PROCESSES];
 pid_t tail_proc = 0;   /* process used by checker-proc */
--- a/selbox.h
+++ b/selbox.h
@@ -1,4 +1,6 @@
-int selection_box(void **list, char *needs_mark, int nlines, char type, int what_help, char *heading);
+#include "mt.h"
+
+int selection_box(void **list, char *needs_mark, int nlines, selbox_type_t type, int what_help, char *heading);
 int select_window(int what_help, char *heading);
 proginfo * select_subwindow(int f_index, int what_help, char *heading);
 char * select_file(char *input, int what_help);