fails to build with GCC 14

[david-geiger]

Hi,

Current source code fails to build with GCC 14 with the following build issue:

In file included from /home/pterjan/rpmbuild/BUILD/tora-3.2/extlibs/dtl/dtl/dtl.hpp:44,
from /home/pterjan/rpmbuild/BUILD/tora-3.2/src/editor/todifftext.cpp:39:
/home/pterjan/rpmbuild/BUILD/tora-3.2/extlibs/dtl/dtl/Diff.hpp: In member function 'void dtl::Diff<elem, sequence, comparator>::enableTrivial() const':
/home/pterjan/rpmbuild/BUILD/tora-3.2/extlibs/dtl/dtl/Diff.hpp:166:27: error: assignment of member 'trivial' in read-only object
166 | this->trivial = true;
| ~~~~~~~~~~~~~~^~~~~~

This PR fixes build: cubicdaiya/dtl#18

[david-geiger]

Also this PR antlr/antlr3#224 is needed to fix build with embedded libantlr3cpp-3.5.3!