[Bug target/82175] [8 Regression] -march=native fails on armv7 big/little system armv7l-unknown-linux-gnueabihf with gcc 8.0.0

[andrewm.roberts at sky dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82175

--- Comment #6 from Andrew Roberts <andrewm.roberts at sky dot com> ---
Thanks Richard, this is now ok, tested on armv7 and aarch64. 

However I do see differences in what is selected by march=native on arm between
7.2.0 and 8.0.0.20171001. Is this as expected? Or is it a work in progress?
There seem to be significant changes...

On aarch64: The only difference is: (< is gcc-7.2.0, > is gcc-8)

<   -mtls-size=                                 [default]
---
>   -mtls-size=                                 24

On armv7: (tested on RPI, and ODROID XU4)
RPI:
<   -march=                                     armv8-a+crc
---
>   -march=                     		armv8-a+crc+simd (RPI)

ODROID XU4:
<   -march=                                     armv7ve
---
>   -march=                                     armv7ve+vfpv3-d16

Differences ommon to both RPI and ODROID XU4:
>   -mbe32                      		[enabled]
>   -mbe8                       		[disabled]

<   -mcpu=                                      [default]
<   -mfix-cortex-m3-ldrd                        [enabled]
---
>   -mcpu=                      		
>   -mfix-cortex-m3-ldrd        		[disabled]

<   -mrestrict-it                               [enabled]
---
>   -mrestrict-it               		[disabled]

<   -mstructure-size-boundary=                  32
---
>   -mstructure-size-boundary=  		8

<   -mthumb-interwork                           [enabled]
---
>   -mthumb-interwork           		[disabled]

<   -mtp=                                       auto
---
>   -mtp=                       		cp15

<   -mtune=                                     [default]
---
>   -mtune=