fix support for arm 32-bit

[silbinarywolf]

The problem

Currently in Zig 0.13.0, building C libraries like SDL2 or OpenXR does not work correctly or as expected. When looking through the various error messages generated it seems that for some reason the C Macro __ARM_ARCH is not set to 7.

Related comment:

zig-android-sdk/src/androidbuild/androidbuild.zig

Lines 154 to 161 in 7f74ebb

	// TODO(jae): 2024-09-08
	// This doesn't work for compiling C code like SDL2 or OpenXR due to "__ARM_ARCH" not being "7"
	// or similar. I might be messing something up here but not sure.
	// .{
	// // arm-linux-androideabi
	// .cpu_arch = .arm,
	// .cpu_features_add = Target.arm.featureSet(&.{.v7a}),
	// },

[silbinarywolf]

Resolved as part of: #16
(At least the build, untested on actual 32-bit ARM device)