Build fails when trying to build gnome-builder from git master using Jhbuild.

The relevant output from compilation log:
Making all in vala-pack
make[3]: Entering directory '/run/media/sadiq/Temp/jhbuild/build/gnome-builder/plugins/vala-pack'
  GEN      libvala_pack_plugin_la_vala.stamp
/home/sadiq/jhbuild/checkout/gnome-builder/plugins/vala-pack/ide-vala-index.vala:76.4-76.27: error: The name `thread' does not exist in the context of `Vala.CodeContext'
			this.code_context.thread = true;
			^^^^^^^^^^^^^^^^^^^^^^^^
/home/sadiq/jhbuild/checkout/gnome-builder/plugins/vala-pack/ide-vala-index.vala:259.7-259.30: error: The name `thread' does not exist in the context of `Vala.CodeContext'
						this.code_context.thread = true;
						^^^^^^^^^^^^^^^^^^^^^^^^
Compilation failed: 2 error(s), 0 warning(s)
Makefile:1112: recipe for target 'libvala_pack_plugin_la_vala.stamp' failed
make[3]: *** [libvala_pack_plugin_la_vala.stamp] Error 1
make[3]: Leaving directory '/run/media/sadiq/Temp/jhbuild/build/gnome-builder/plugins/vala-pack'
Makefile:615: recipe for target 'all-recursive' failed
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory '/run/media/sadiq/Temp/jhbuild/build/gnome-builder/plugins'
Makefile:652: recipe for target 'all-recursive' failed