package/xenomai: set 'custom' as version in case of tarball

When BR2_PACKAGE_XENOMAI_CUSTOM_TARBALL is selected, the xenomai package
declared an empty version, which among others means that the build directory
becomes output/build/xenomai without any version specification, and empty
version information in 'xenomai-show-info'.

Other packages that allow a custom tarball, like 'linux' and
'arm-trusted-firmware', specify 'custom' as version in this case.

Adapt the xenomai package accordingly.

Signed-off-by: Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit 603bfafa97ed148fb7774cac7f644eb575535a05)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/xenomai/Config.in

@@ -69,9 +69,11 @@ config BR2_PACKAGE_XENOMAI_REPOSITORY
 	depends on BR2_PACKAGE_XENOMAI_CUSTOM_GIT
 
 config BR2_PACKAGE_XENOMAI_VERSION
-	string "Custom Xenomai version" if !BR2_PACKAGE_XENOMAI_LATEST_VERSION
+	string "Custom Xenomai version" if \
+		!BR2_PACKAGE_XENOMAI_LATEST_VERSION && \
+		!BR2_PACKAGE_XENOMAI_CUSTOM_TARBALL
 	default "3.0.10" if BR2_PACKAGE_XENOMAI_LATEST_VERSION
-	depends on !BR2_PACKAGE_XENOMAI_CUSTOM_TARBALL
+	default "custom" if BR2_PACKAGE_XENOMAI_CUSTOM_TARBALL
 
 config BR2_PACKAGE_XENOMAI_CUSTOM_TARBALL_URL
 	string "URL of custom tarball"