Fix angelscript build on non-x86 arches - fixes #2119 and fixes #2194

[jcowgill]

This is my fix for #2119 and #2194. I have compile tested it on x86_64 and mips64el. Incredibly I have no ARM hardware so I am currently building it there with QEMU. That'll probably take at least another hour though.

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For the build failures on 64-bit arches, angelscript was using __LP64__ to test for x86_64. Use the correct define instead.

For ARM architectures, ensure the native function calling file is built on all ARM arches and not just when building for android.

[jcowgill]

The original ARM build failed, but adding -Wa,-mimplicit-it=always to the compile options for the assembly file makes it build successfully.

[auriamg]

Thanks for the pull requests, though since some parts affect angelscript directly, I will try to get these changes upstream

EDIT: After verifying, these architectures actually do not appear to be supported by angelscript ( see http://www.angelcode.com/angelscript/features.html ) - they are also pretty uncommon architectures so I don't think we care STK not running there

[Vincent-C]

@jcowgill It looks like only armel FTBFS now:

/«PKGBUILDDIR»/lib/angelscript/source/as_callfunc_arm_gcc.S: Assembler messages:
/«PKGBUILDDIR»/lib/angelscript/source/as_callfunc_arm_gcc.S:88: Error: selected processor does not support ARM mode `blx r4'
/«PKGBUILDDIR»/lib/angelscript/source/as_callfunc_arm_gcc.S:136: Error: selected processor does not support ARM mode `blx r4'
/«PKGBUILDDIR»/lib/angelscript/source/as_callfunc_arm_gcc.S:183: Error: selected processor does not support ARM mode `blx r4'
/«PKGBUILDDIR»/lib/angelscript/source/as_callfunc_arm_gcc.S:221: Error: selected processor does not support ARM mode `blx r4'
/«PKGBUILDDIR»/lib/angelscript/source/as_callfunc_arm_gcc.S:258: Error: selected processor does not support ARM mode `blx r4'

Not knowing how portable the ARM assembly in angelscript actually is...perhaps it's best to just use the AS_MAX_PORTABILITY define for armel? Is there a way to distinguish armel from armhf/arm64?

@auriamg Not sure if you saw @jcowgill's reply in #2194 or not, but that page does mention that angelscript is supported for arm, amongst a variety of other CPU architectures.

[jcowgill]

Lovely, blx is an ARMv5 instruction and Debian armel is only ARMv4t. Looking at the source (bear in mind I don't know ARM very well), it also uses a lot of ldmia ... pc instructions which don't cause the correct Thumb mode change on ARMv4t, but do on ARMv5. So I think the best solution is to just disable the ARM assembly parts on v4 until they can be fixed (if that ever happens).

Is there a way to distinguish armel from armhf/arm64?

Yes __ARM_ARCH_4T__ is defined on armel, but not the others. I'll push a fix to disable it there in a minute.

[hiker]

@auriamg This sounds like a patch to be potentially useful upstream (in case that they want to support those platforms), but not for us at this stage then. Can it be closed?

[auriamg]

Given that STK doesn't support those architectures then I would agree this should be submitted upstream, not here. Closing this PR