package/oracle-mysql: fix build with autoconf >= 2.70

package/oracle-mysql: fix build with autoconf >= 2.70

Fix the following build failure raised since bump of autoconf to version
2.71 in commit ecd54b65c1f998a7ccd91f7c523e4ff38c4781da:

autoheader: warning: missing template: CRAY_STACKSEG_END
autoheader: warning: Use AC_DEFINE([CRAY_STACKSEG_END], [], [Description])
autoreconf: error: /home/buildroot/autobuild/instance-2/output-1/host/bin/autoheader failed with exit status: 1
package/pkg-generic.mk:273: recipe for target '/home/buildroot/autobuild/instance-2/output-1/build/oracle-mysql-5.1.73/.stamp_configured' failed

Fixes:
 - http://autobuild.buildroot.org/results/e5329bcf166d46b2eb17f2bc727c0307bef5ed02

Signed-off-by: Fabrice Fontaine <[email protected]>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <[email protected]>