* src/bridge.c, src/bridge.h, src/qemu_conf.c, src/qemu_conf.h,
src/qemu_driver.c, src/qemu_driver.h, src/test.c: Disable more
of qemu if configured --without-qemu.
Avoid risk of format string abuse (also avoids gcc warnings).
* src/util.c (ReportError): Use a literal "%s" format string.
* src/remote_internal.c (server_error): Likewise.
* src/qemu_conf.c (qemudReportError): Likewise.
* acinclude.m4: Add -Wformat -Wformat-security to default
list of warning flags, to warn about errors such as the
above.
* acinclude.m4, configure.in: ./configure option
--disable-stack-protector.
* src/gnutls_1_0_compat.h: Compatibility with GnuTLS 1.0.
* src/bridge.c: If no bridge ioctls, give an error at runtime.
