Fix ARMv6 Linux cross-build

Fix ARMv6 Linux cross-build

related #29676

R=rmacnak@google.com

Committed: https://github.com/dart-lang/sdk/commit/34f601a8dbd43ed5c9bdbace7a547769e4c03472

[zra, 2017-05-22 03:25:11]

zra@google.com changed reviewers:
+ rmacnak@google.com

[rmacnak, 2017-05-22 16:03:04]

On 2017/05/22 03:25:11, zra wrote:

I get a link error:

/usr/local/google/home/rmacnak/cross/pi/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin/../lib/gcc/arm-linux-gnueabihf/4.8.3/../../../../arm-linux-gnueabihf/bin/ld:
error: ./process_test uses VFP register arguments,
obj/runtime/bin/process_test/process_test.o does not
/usr/local/google/home/rmacnak/cross/pi/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin/../lib/gcc/arm-linux-gnueabihf/4.8.3/../../../../arm-linux-gnueabihf/bin/ld:
failed to merge target specific data of file
obj/runtime/bin/process_test/process_test.o

Maybe the compiler and linker aren't getting consistent flags?

[zra, 2017-05-22 17:45:54]

I've added a gn.py argument that allows specifying the float ABI. When using the
hf or hardfp toolchains for ARMv6, you can pass "--arm-float-abi hard" and it
should build.

[rmacnak, 2017-05-22 19:42:55]

lgtm

[zra, 2017-05-22 20:15:37]

Description was changed from

==========
Fix ARMv6 Linux cross-build

related #29676
==========

to

==========
Fix ARMv6 Linux cross-build

related #29676

R=rmacnak@google.com

Committed:
https://github.com/dart-lang/sdk/commit/34f601a8dbd43ed5c9bdbace7a547769e4c03472
==========

[zra, 2017-05-22 20:15:38]

Committed patchset #2 (id:20001) manually as
34f601a8dbd43ed5c9bdbace7a547769e4c03472 (presubmit successful).