Include Linux atomic emulation on androideabi

[ghost]

The old androideabi uses armv5 and thus also needs the atomic emulation and because Android is basically Linux it can use the same implementation.

This has been verified by taking a old libgcc from a ndk toolchain to a dissassembler:

__sync_fetch_and_add_4 as an example

00000000 <__sync_fetch_and_add_4>:
       0: f8 40 2d e9  	push	{r3, r4, r5, r6, r7, lr}
       4: 28 60 9f e5  	ldr	r6, [pc, #40]
       8: 00 50 a0 e1  	mov	r5, r0
       c: 01 70 a0 e1  	mov	r7, r1
      10: 00 40 95 e5  	ldr	r4, [r5]
      14: 05 20 a0 e1  	mov	r2, r5
      18: 04 00 a0 e1  	mov	r0, r4
      1c: 07 10 84 e0  	add	r1, r4, r7
      20: 36 ff 2f e1  	blx	r6
      24: 00 00 50 e3  	cmp	r0, #0
      28: f8 ff ff 1a  	bne	#-32 <__sync_fetch_and_add_4+0x10>
      2c: 04 00 a0 e1  	mov	r0, r4
      30: f8 80 bd e8  	pop	{r3, r4, r5, r6, r7, pc}

00000034 <$d>:
      34:	c0 0f ff ff	.word	0xffff0fc0

0xffff0fc0 being the address of the kuser function kuser_cmpxchg.

Reason for this change: rust-lang/rust#85806 (comment)

[ghost]

Would you mind publishing a new version, so that these changes can be included in the rust repository?

[Amanieu]

Published 0.1.44.

[dcsommer]

@ATiltedTree just a heads up this was partially reverted in #450