When not logging I/O install a handler for SIGCONT and deliver it

to the command upon resume.  Fixes bugzilla #431

src/exec.c

@@ -96,8 +96,15 @@ static int fork_cmnd(struct command_details *details, char *argv[],
     char *envp[], int sv[2])
 {
     struct command_status cstat;
+    sigaction_t sa;
     int pid;
 
+    zero_bytes(&sa, sizeof(sa));
+    sigemptyset(&sa.sa_mask);
+    sa.sa_flags = SA_INTERRUPT; /* do not restart syscalls */
+    sa.sa_handler = handler;
+    sigaction(SIGCONT, &sa, NULL);
+
     pid = fork();
     switch (pid) {
     case -1: