gcc-7 did take less time to compile it, though
trying clang-7, took some time to find the right triple: -target x86_64-pc-mingw32
(though I haven't checked yet that it links correctly)
I think I'll punt these compiler changes to a future `kf-2.15` branch, the generated code for reference and perturbation iterations is just not good enough yet.
Would be nice though, adding a formula would become 2 lines of code, and the huge formula.cpp generated from the semi-automatically crafted formula.xml via formua.xsl takes a long time to compile, at least the generated code is split into many files so it can be compiled in parallel...
Hopefully will manage to release `kf-2.14.4` today with some less invasive changes.