Not having any success unfortunately. Trying to build r383 with either GMP-6.2.0 or 6.1.2 fails with

Code:

arith/monty.c:36:17: error: redefinition of '_umul128'
36 | __inline uint64 _umul128(uint64 a, uint64 b, uint64 *c)
| ^~~~~~~~
In file included from C:/msys64/mingw64/x86_64-w64-mingw32/include/intrin.h:41,
from include/types.h:38,
from include/yafu.h:50,
from arith/monty.c:26:
C:/msys64/mingw64/x86_64-w64-mingw32/include/psdk_inc/intrin-impl.h:979:18: note: previous definition of '_umul128' was here
979 | unsigned __int64 _umul128(unsigned __int64 a, unsigned __int64 b, unsigned __int64 *hi)
| ^~~~~~~~
arith/monty.c: In function '_umul128':
arith/monty.c:39:12: warning: unused variable 'lo' [-Wunused-variable]
39 | uint64 lo = (uint64)result;
| ^~
arith/monty.c: In function 'fp_montgomery_calc_normalization':
arith/monty.c:51:12: warning: unused variable 'bits' [-Wunused-variable]
51 | int x, bits;
| ^~~~
arith/monty.c:51:9: warning: unused variable 'x' [-Wunused-variable]
51 | int x, bits;
| ^
arith/monty.c: In function 'mulmod128':
arith/monty.c:382:9: warning: variable 's' set but not used [-Wunused-but-set-variable]
382 | uint64 s[3];
| ^
arith/monty.c: In function 'sqrmod128':
arith/monty.c:493:9: warning: variable 's' set but not used [-Wunused-but-set-variable]
493 | uint64 s[3];
| ^
arith/monty.c: In function '_umul128':
arith/monty.c:41:1: warning: control reaches end of non-void function [-Wreturn-type]
41 | }
| ^
make: *** [Makefile.mingw:286: arith/monty.o] Error 1

I managed to build r379 with GMP-6.1.2, but on the Nehalem it crashes on SIQS jobs larger than ~70 digits (same for the last binary I posted -

edit: Madpoo I see you found this too). It's entirely possible that building for a Nehalem on a Kaby Lake requires more care than I've been taking; I'm giving up for now.