NumPy build on older processor X86_V2 glitch

[Jim Spath <jspath55%gmail.com@localhost>]

I have been building QGIS 3 on older machines I have, to check out the
range of PostgreSQL database support. On one Intel machine, I get
errors on py-numpy, so the dependency py-gdal won't build. Running a
QGIS version built on an AMD says the processor is missing X86_V2:

RuntimeError: NumPy was built with baseline optimizations: (X86_V2)
but your machine doesn't support:(X86_V2).
Python version: 3.13.12 (main, Jun 1 2026, 09:01:00) [GCC 12.5.0]
QGIS version: 3.44.11-Solothurn 'Solothurn', exported

Except if I build py-numpy on the Intel machine the tests say the
processor is OK:

[...]
Program python found: YES (/usr/pkg/bin/python3.13)
Found pkg-config: YES
(/usr/pkgsrc/math/py-numpy/work/.tools/bin/pkg-config) 2.5.1
Run-time dependency python found: YES 3.13
Has header "Python.h" with dependency python-3.13: YES
Compiler for C supports arguments -fno-strict-aliasing: YES
Test features "X86_V2" : Supported
Test features "X86_V3" : Supported
Test features "X86_V4" : Supported
Test features "AVX512_ICL" : Supported

Failed machine:
hw.model = Intel 686-class
machdep.dmi.processor-vendor = GenuineIntel
machdep.dmi.processor-version = Intel(R) Core(TM)2 Duo CPU     L9400  @ 1.86GHz
machdep.cpu_brand = Intel(R) Core(TM)2 Duo CPU     L9400  @ 1.86GHz

OK machine:
hw.machine = amd64
hw.model = AMD 686-class
machdep.dmi.processor-vendor = AuthenticAMD
machdep.dmi.processor-version = AMD A8-6410 APU with AMD Radeon R5 Graphics
machdep.cpu_brand = AMD A8-6410 APU with AMD Radeon R5 Graphics

Jim