Set the stdin pipe to non-blocking

src/runner.cpp

@@ -2,6 +2,7 @@
 
 #include <array>
 #include <cerrno>
+#include <fcntl.h>
 #include <poll.h>
 #include <spawn.h>
 #include <system_error>
@@ -19,6 +20,10 @@ run_result runner::run_blocking(const program &program) {
         throw std::system_error{errno, std::generic_category()};
     }
 
+    // Avoid blocking on stdin, and being interrupted if the pipe is closed prematurely
+    int flags = fcntl(in_pipe[1], F_GETFL, 0);
+    fcntl(in_pipe[1], F_SETFL, flags | O_NONBLOCK);
+
     posix_spawn_file_actions_t actions;
     posix_spawn_file_actions_init(&actions);
     posix_spawn_file_actions_addclose(&actions, in_pipe[1]);