Update to 6.3.0

Changelog:
* The default mode for C++ is now -std=gnu++14 instead of -std=gnu++98.

# ARM

Support for revisions of the ARM architecture prior to ARMv4t has been
deprecated and will be removed in a future GCC release. The -mcpu and
-mtune values that are deprecated are: arm2, arm250, arm3, arm6,
arm60, arm600, arm610, arm620, arm7, arm7d, arm7di, arm70, arm700,
arm700i, arm710, arm720, arm710c, arm7100, arm7500, arm7500fe, arm7m,
arm7dm, arm7dmi, arm8, arm810, strongarm, strongarm110, strongarm1100,
strongarm1110, fa526, fa626. The value arm7tdmi is still
supported. The values of -march that are deprecated are:
armv2,armv2a,armv3,armv3m,armv4.

The ARM port now supports target attributes and pragmas. Please refer
to the documentation for details of available attributes and pragmas
as well as usage instructions.

Support has been added for the following processors (GCC identifiers
in parentheses): ARM Cortex-A32 (cortex-a32), ARM Cortex-A35
(cortex-a35) and ARM Cortex-R8 (cortex-r8). The GCC identifiers can be
used as arguments to the -mcpu or -mtune options, for example:
-mcpu=cortex-a32 or -mtune=cortex-a35.


(ryoon)