Fix X-PREPROCESS exec to wait pid

src/switch_xml.c

@@ -56,6 +56,7 @@
 
 #include <switch.h>
 #ifndef WIN32
+#include <sys/wait.h>
 #include <switch_private.h>
 #include <glob.h>
 #else /* we're on windoze :( */
@@ -1245,6 +1246,7 @@ static int preprocess_exec(const char *cwd, const char *command, int write_fd, i
 				}
 			}
 			close(fds[0]);
+			waitpid(pid, NULL, 0);
 		} else {				/*  child */
 			close(fds[0]);
 			dup2(fds[1], STDOUT_FILENO);