Leaf package on ix86: drop ix86 support

Rebuilt for gtest 1.13.0 (fix RHBZ#2164003)
Build with C++14 instead of C++11, since gtest dropped support
Add a missing #include directive for GCC 13

Remove old easylogging++ sources from dist-git

Rebuilt for https://fedoraproject.org/wiki/Fedora_38_Mass_Rebuild

Tidy up spec file formatting

Stop numbering patches

Unbundle easyloggingpp

Improve treatment of bundled sundials(2)
Unbundling currently works up to linking, where there are undefined

Use more standard macros where we can

Add -DCMAKE_INSTALL_DO_STRIP:BOOL=OFF to match %%cmake

Use pkgconf to set unbundled gtest flags

Simplify patch application

Better handle bundled easyloggingpp dependency

Remove unbundled dependencies in %%prep

Remove workaround for pre-flexiblas Fedora versions

Reduce macro indirection in the spec file