Description of problem:
Build of valabind package on Fedora 21 or Rawhide FTBFS, apparently due to the upgrade of vala from 0.22 to 0.25.  Happens even with newer valabind 0.8.0 relese.

Version-Release number of selected component (if applicable):
valabind 0.7.4-5
vala 0.25

How reproducible:
100%

Steps to Reproduce:
attempt to build valabind RPM for Fedora 21 or rawhide

Expected results:
successful build

Actual results:

Compiling config.vala main.vala valabindwriter.vala nodeffiwriter.vala utils.vala girwriter.vala swigwriter.vala cxxwriter.vala ctypeswriter.vala dlangwriter.vala -> valabind
valac -g --cc="cc" -X -O2 -X -g -X -pipe -X -Wall -X -Werror=format-security -X -Wp,-D_FORTIFY_SOURCE=2 -X -fexceptions -X -fstack-protector-strong -X --param=ssp-buffer-size=4 -X -grecord-gcc-switches -X -m64 -X -mtune=generic -X -Wl,-z,relro -o valabind --pkg posix --pkg libvala-0.26 --save-temps  config.vala main.vala valabindwriter.vala nodeffiwriter.vala utils.vala girwriter.vala swigwriter.vala cxxwriter.vala ctypeswriter.vala dlangwriter.vala 
swigwriter.vala:88.34-88.45: error: Argument 1: Cannot convert from `Vala.Expression?' to `int'
            return element+"[%d]".printf (array.length); // FIXME will this work?
                                          ^^^^^^^^^^^^
swigwriter.vala:262.52-262.63: error: Argument 1: Cannot convert from `Vala.Expression?' to `int'
            field = element + " " + f.name + "[%d]".printf (array.length); // FIXME will this work?
                                                            ^^^^^^^^^^^^
nodeffiwriter.vala:70.46-70.57: error: Argument 1: Cannot convert from `Vala.Expression?' to `int'
            return "_.array("+element+", %d)".printf (array.length);
                                                      ^^^^^^^^^^^^
ctypeswriter.vala:209.41-209.52: error: Argument 1: Cannot convert from `Vala.Expression?' to `int'
            return "'"+element+"', * %d".printf (array.length); // FIXME will this work?
                                                 ^^^^^^^^^^^^
ctypeswriter.vala:411.53-411.64: error: Argument 3: Cannot convert from `Vala.Expression?' to `int'
            field = "'%s', %s * %d".printf (f.name, element, array.length);
                                                             ^^^^^^^^^^^^
dlangwriter.vala:184.10-184.26: error: Assignment: Cannot convert from `Vala.Expression?' to `int'
                    int sz = array.length;
                        ^^^^^^^^^^^^^^^^^
dlangwriter.vala:185.51-185.52: error: The name `sz' does not exist in the context of `DlangWriter.walk_field'
                    defs += "  %s %s[%d];\n".printf (type, name, sz);
                                                                 ^^
Compilation failed: 7 error(s), 0 warning(s)


Additional info:

Can fix (or at least prevent compiler complaints) for the array.length errors by patching in explict casts to int.  Need upstream help for the sz problem, though.

Upstream issue: https://github.com/radare/valabind/issues/28