[libgda] Enable VALA_API_VERSION environment variable

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit 9afeef02b2a55b260e9287fcceed39b9b14d391c
Author: Daniel Espinosa <esodan gmail com>
Date:   Fri Jun 5 14:23:28 2015 -0500

    Enable VALA_API_VERSION environment variable
    
    * You can set VALA_API_VERSION or set on ./configure command line
      to set required Vala API to use, this will check correspoding
      versioned package

 configure.ac |   15 +++++++++++++--
 1 files changed, 13 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index cd37ee1..f9c2103 100644
--- a/configure.ac
+++ b/configure.ac
@@ -537,6 +537,8 @@ AM_CONDITIONAL(ENABLE_GI_SYSTEM_INSTALL, [test x"$enable_gi_system_install" = "x
 dnl ******************************
 dnl Check for Vala Compiler
 dnl ******************************
+AC_ARG_VAR(VALA_API_VERSION,[Vala API version to generate bingdings and compile against. Install versioned 
bidings.])
+
 if test "x$enable_gda_gi" != "xyes" -a "x$enable_gdaui_gi" = "xyes"
 then
        AC_MSG_ERROR([GObject Introspection for GDA-UI is requested but GObject Introspection for GDA is 
disabled. Use --enable-gda-gi])
@@ -565,10 +567,18 @@ then
        AC_MSG_ERROR([Vala Extensions (Utility GObject clases written in Vala) is requested but Vala Bindings 
is disable. Use --enable-vala])
 fi
 
+vala_api="No Vala bindings will be generated"
 if test "x$enable_vala" = "xyes"
 then
-       AM_PROG_VALAC([0.17.7])
-       VAPIGEN_CHECK([0.17.7],[0.26],,no)
+       AM_PROG_VALAC([0.26.0])
+       if test "x$VALA_API_VERSION" = "x"
+       then
+               VAPIGEN_CHECK([0.26.0],[0.26],,no)
+               vala_api="0.26 (Default)"
+       else
+               VAPIGEN_CHECK([0.26.0],$VALA_API_VERSION,,no)
+               vala_api=$VALA_API_VERSION
+       fi
 else
        AM_CONDITIONAL(ENABLE_VAPIGEN,false)
 fi
@@ -1089,6 +1099,7 @@ echo "   Building libgda-ui GObject Introspection: `if test x$enable_gdaui_gi !=
 echo "   Building Gtk-Doc: `if test x$enable_gtk_doc != xno; then echo yes; else echo no; fi`"
 echo "   Building Help (GdaBrowser): `if test x$with_gdu != xno; then echo yes; else echo no; fi`"
 echo "   Building GDA Vala Bindings (--enable-vala): `if test x$vapigen_pkg_found != xyes; then echo no; 
else echo yes; fi`"
+echo "     Vala API version to use: $vala_api"
 echo "   Building GDA-UI Vala Bindings: `if test x$enable_gdaui_vala != xyes; then echo no; else echo yes; 
fi`"
 echo "   Building Vala Extensions: `if test x$enable_vala_ext != xno; then echo yes; else echo no; fi`"
 echo "   Building Vala Documentation: `if test x$enable_vala_doc != xno; then echo yes; else echo no; fi`"