implement 'keypressed()' in the unix port

Signed-off-by: Simon Goldschmidt <goldsimon@gmx.de>

contrib/ports/unix/port/include/arch/sys_arch.h

@@ -59,5 +59,8 @@ typedef struct sys_mbox * sys_mbox_t;
 struct sys_thread;
 typedef struct sys_thread * sys_thread_t;
 
+#define LWIP_EXAMPLE_APP_ABORT() lwip_unix_keypressed()
+int lwip_unix_keypressed(void);
+
 #endif /* LWIP_ARCH_SYS_ARCH_H */
 

contrib/ports/unix/port/sys_arch.c

@@ -717,3 +717,14 @@ sys_arch_unprotect(sys_prot_t pval)
     }
 }
 #endif /* SYS_LIGHTWEIGHT_PROT */
+
+/* get keyboard state to terminate the debug app by using select */
+int
+lwip_unix_keypressed(void)
+{
+  struct timeval tv = { 0L, 0L };
+  fd_set fds;
+  FD_ZERO(&fds);
+  FD_SET(0, &fds);
+  return select(1, &fds, NULL, NULL, &tv);
+}