FIX: resolving last error id on posix platforms, if provided value to…

… Make_OS-Error is zero (on Windows there is already used GetLastError in such a situation)

src/core/f-stubs.c

@@ -864,6 +864,10 @@
 **
 */	REBVAL *Make_OS_Error(int errnum)
 /*
+**      Creates Rebol string from error number.
+**      If errnum is zero, the number of last error will be resolved
+**      using system functions.
+**
 ***********************************************************************/
 {
 	REBCHR str[100];

src/os/posix/host-lib.c

@@ -420,6 +420,7 @@ int pipe2(int pipefd[2], int flags); //to avoid "implicit-function-declaration"
 **
 ***********************************************************************/
 {
+    if (!errnum) errnum = errno;
 	strerror_r(errnum, s_cast(str), len);
 	return str;
 }
@@ -1280,9 +1281,14 @@ static int Try_Browser(char *browser, REBCHR *url)
 			exit(1);
 			break;
 		default:
-			waitpid(pid, &status, WUNTRACED);
-			result = WIFEXITED(status)
+            sleep(1); // needed else WEXITSTATUS sometimes reports value 127
+            if (0 > waitpid(pid, &status, WUNTRACED)) {
+                result = FALSE;
+            } else {
+                printf("status: %i WIFEXITED: %i WEXITSTATUS: %i\n", status, WIFEXITED(status), WEXITSTATUS(status) );
+                result = WIFEXITED(status)
 					&& (WEXITSTATUS(status) == 0);
+            }
 	}
 
 	return result;