Modernize vala binding generation

Modernize vala binding generation

Use vapigen.m4 and Makefile.vapigen from vala to handle vapi file
generation.  Also generate vapi always when gir is updated.

BUG=none

Committed: 58accdc

[Daiki Ueno, 2012-12-01 08:11:04]

https://live.gnome.org/Vala/UpstreamGuide#Autotools_Integration

[Peng, 2012-12-03 13:27:59]

On 2012/12/01 08:11:04, Daiki Ueno wrote:
> https://live.gnome.org/Vala/UpstreamGuide#Autotools_Integration

lgtm

[Daiki Ueno, 2012-12-04 03:22:47]

On 2012/12/03 13:27:59, Peng wrote:
> On 2012/12/01 08:11:04, Daiki Ueno wrote:
> > https://live.gnome.org/Vala/UpstreamGuide#Autotools_Integration
> 
> lgtm

Forgot to mention that this requires vala 0.16.
Is it ok to assume vala 0.16?  The current vala release is 0.18 and 0.16 is
available for Debian testing and Ubuntu oneiric at least.

By the way, probably we should create tarballs with automake 1.12.5, that
doesn't fail when vala compiler is too old.

[Peng, 2012-12-04 15:46:46]

On 2012/12/04 03:22:47, Daiki Ueno wrote:
> On 2012/12/03 13:27:59, Peng wrote:
> > On 2012/12/01 08:11:04, Daiki Ueno wrote:
> > > https://live.gnome.org/Vala/UpstreamGuide#Autotools_Integration
> > 
> > lgtm
> 
> Forgot to mention that this requires vala 0.16.
> Is it ok to assume vala 0.16?  The current vala release is 0.18 and 0.16 is
> available for Debian testing and Ubuntu oneiric at least.
I think it should be OK. We just need make sure ibus can be built without vala
(without gtk3 ui).

> 
> By the way, probably we should create tarballs with automake 1.12.5, that
> doesn't fail when vala compiler is too old.

[Peng, 2012-12-06 19:30:22]

https://codereview.appspot.com/6849132/diff/4002/configure.ac
File configure.ac (right):

https://codereview.appspot.com/6849132/diff/4002/configure.ac#newcode123
configure.ac:123: AM_PROG_VALAC([0.16])
I modified here to 0.14, and generate a tarball and tested it with vala-0.14. I
did not find any problem during building. I guess vala-0.16 is only needed for
generating configure. Is it right? In that case, I suggest using 0.14 here.

[Daiki Ueno, 2012-12-06 20:52:33]

https://codereview.appspot.com/6849132/diff/4002/configure.ac
File configure.ac (right):

https://codereview.appspot.com/6849132/diff/4002/configure.ac#newcode123
configure.ac:123: AM_PROG_VALAC([0.16])
On 2012/12/06 19:30:22, Peng wrote:
> I modified here to 0.14, and generate a tarball and tested it with vala-0.14.
I
> did not find any problem during building. I guess vala-0.16 is only needed for
> generating configure. Is it right? In that case, I suggest using 0.14 here.

Not exactly, but changing it back to 0.14 should be fine. 

vala-0.16 is needed for generating *.vapi using Makefile.vapgen, which is
available since 0.16.  So be careful when generating tarballs.