Choose a baseline ISA for CLANGARM64 builds

[hmartinez82]

More and more packages are being built for CLANGARM64, but it occurred to me that we may be leaving some performance on the table.

Of course, it's better to have a native build first regardless of optimizations, but in light of this llvm/llvm-project#66912 being fixed it got me wondering:

• We should at least make sure that projects that are already using NEON are enabling NEON in Windows builds
• We should pick a baseline ISA

Bellow is, definitely not complete, possibly not correct, list of Windows on ARM laptops with their respective cores and supported baseline ISAs

Laptop Name	Year Launched	CPU Name	big Core	LITTLE Core	ISA
Asus NovaGo	2018	Snapdragon 835	Cortex-A73	Cortex-A53	ARMv8
HP Envy x2	2018	Snapdragon 835	Cortex-A73	Cortex-A53	ARMv8
Lenovo Miix 630	2018	Snapdragon 835	Cortex-A73	Cortex-A53	ARMv8
Samsung Galaxy Book2	2018	Snapdragon 850	Cortex-A75	Cortex-A55	ARMv8.2
Huawei Matebook E (2019)	2019	Snapdragon 850	Cortex-A75	Cortex-A55	ARMv8.2
Microsoft Surface Pro X	2019	Microsoft SQ1	Cortex-A76	Cortex-A55	ARMv8.2
Lenovo Yoga 5G	2020	Snapdragon 8cx	Cortex-A76	Cortex-A55	ARMv8.2
Samsung Galaxybook S	2020	Snapdragon 8cx	Cortex-A76	Cortex-A55	ARMv8.2
Microsoft Surface Pro X (SQ2)	2020	Microsoft SQ2	Cortex-A76	Cortex-A55	ARMv8.2
Lenovo Yoga 5G	2020	Snapdragon 8cx	Cortex-A76	Cortex-A55	ARMv8.2
Acer Spin 7	2021	Snapdragon 8cx Gen 2	Cortex-A76	Cortex-A55	ARMv8.2
Microsoft Surface Pro 9 with 5G	2023	Microsoft SQ3	Cortex-X1	Cortex-A78	ARMv8.2
Lenovo ThinkPad X13s	2023	Snapdragon 8cx Gen 3	Cortex-X1	Cortex-A78	ARMv8.2
Samsung Galaxy Book2 Pro	2023	Snapdragon 8cx Gen 3	Cortex-X1	Cortex-A78	ARMv8.2

Does that mean that -mtune should stay as cortex-a53

@Blackhex, @dennisameling feel free to chime in or tag anyone you think knows a lot about this.

[Biswa96]

Just don't break Raspberry Pi 4 support 🙏

[hmartinez82]

Device Name	Year Launched	CPU Name	Core	ISA
Raspberry Pi 4 Model B	2019	Broadcom BCM2711	Cortex-A72	ARMv8
Raspberry Pi 5	2023	Broadcom BCM2712	Cortex-A76	ARMv8.2

@Biswa96 ^ 😉 for completion

[Blackhex]

cc @ZacWalk @movediedi