gtkmathview: fix build error
When building, I was seeing the following error which this patch fixes:
../../../src/frontend/common/TemplateElementIterator.hh:46:18: error:
'valid' was not declared in this scope, and no declarations were found by
argument-dependent lookup at the point of instantiation [-fpermissive]
Upstream-Status: Submitted [padovani .at. di .dot. unito .dot. it]
(From meta-openembedded rev:
49cb8758eb9c610364ad4e0f13d31d10fc48899f)
Signed-off-by: Trevor Woerner <trevor.woerner@linaro.org>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>