Add interruptible function to read from pipe

This will avoid to block Ctrl+c if the process the pipe is read from
takes too much time.

app/src/util/process_intr.h

@@ -10,4 +10,12 @@ bool
 sc_process_check_success_intr(struct sc_intr *intr, sc_pid pid,
                               const char *name, bool close);
 
+ssize_t
+sc_pipe_read_intr(struct sc_intr *intr, sc_pid pid, sc_pipe pipe, char *data,
+                  size_t len);
+
+ssize_t
+sc_pipe_read_all_intr(struct sc_intr *intr, sc_pid pid, sc_pipe pipe,
+                      char *data, size_t len);
+
 #endif