[Buildroot] [PATCH v2 1/5] package/gdb: rework dependency for C++11

[Yann E. MORIN]

Thomas, All,

On 2018-02-07 13:36 +0100, Thomas Petazzoni spake thusly:
> On Wed, 7 Feb 2018 10:58:28 +0100, Yann E. MORIN wrote:
[--SNIP--]
> > > +config BR2_PACKAGE_GDB_NEEDS_CXX11
> > > +	bool
> > > +	default y
> > > +	depends on !BR2_GDB_VERSION_7_10
> > > +	depends on !BR2_GDB_VERSION_7_11
> > > +	depends on !BR2_GDB_VERSION_7_12  
> > I would have expected that the various versions would select this,
> > i.e. something like:
> > 
> >     config BR2_PACKAGE_GDB_NEEDS_CXX11
> >         bool
> > 
> > 
> >     config BR2_GDB_VERSION_7_10
> >         bool "7.10"
> > 
> >     config BR2_GDB_VERSION_8_0
> >         bool "8.0"
> >         select BR2_PACKAGE_GDB_NEEDS_CXX11
> 
> But this doesn't work; The BR2_GDB_VERSION_8_0 symbol is only enabled
> if we build a host variant of gdb. If we build just the target
> variant, then no version is selected at all, and therefore this symbol
> would not be selected.

Gah, I missed that...

> So in fact, even my code is slightly wrong: it becomes correct once the
> default version of gdb is 8.0, but it is wrong when the default version
> is still 7.12 (which is the case at the time my patch is introduced).
> 
> Indeed, when my patch is introduced, 7.12 is the default gdb version,
> used if you build only the target gdb. When you build just the target
> gdb version, BR2_GDB_VERSION_7_12 is not enabled, and therefore
> BR2_PACKAGE_GDB_NEEDS_CXX11=y even if it's not true.
> 
> So I should adjust that. I could use the BR2_GDB_VERSION string
> option, which exists regardless of whether host gdb is enabled or not.
> Or I could rely on BR2_PACKAGE_HOST_GDB somehow.
> 
> Meh. This is crappy :)

OK, I think I have an idea about all this mess... But since I can have
pretty weird ideas, I make no promise that it will materialise into
something usefull...

Regards,
Yann E. MORIN.

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