test_qemu: Improve the error message.

Note that errno is probably not set to a useful value here, so there
is not much point recording it.

diff --git a/src/launch.c b/src/launch.c
index 11d1acf..03ad39b 100644 (file)
--- a/src/launch.c
+++ b/src/launch.c
@@ -1083,7 +1083,8 @@ test_qemu (guestfs_h *g)
    * probably indicates that the qemu binary is missing.
    */
   if (test_qemu_cmd (g, cmd, &g->qemu_help) == -1) {
-    perrorf (g, _("%s: command failed: If qemu is located on a non-standard path, try setting the LIBGUESTFS_QEMU environment variable."), cmd);
+    error (g, _("command failed: %s\n\nIf qemu is located on a non-standard path, try setting the LIBGUESTFS_QEMU\nenvironment variable.  There may also be errors printed above."),
+           cmd);
     return -1;
   }