RFR: JDK-8215296 do not disable c99 on Solaris

[Kim Barrett]

> On Dec 12, 2018, at 5:17 PM, David Holmes <david.holmes at oracle.com> wrote:
> 
> Hi Magnus,
> 
> What did -Xa do?

From the documentation for -Xa:

The -X options cannot be used if the -std has been specified.

The -X options specify varying degress of compliance to the 1990 and 1999
ISO C standard. ...

-Xa
ISO C plus K&R C compatibility extensions with semantic changes
required by ISO C. Where K&R C and ISO C specify different semantics
for the same construct, the compiler uses the ISO C interpretation. If
the -Xa option is used in conjunction with the -xtransition option, the
compiler issues warnings about the different semantics.

The default mode for the compiler is -std=c11.

> Do AWT folk need to check this. I find it hard to understand the connection between:
> 
> -xc99=no_lib
> 
> and
> 
> -D_XPG6
> 
> ??

I was wondering the same thing about -D_XPG6.