[wip]: gir xml schema

reset && time find /home/dieterv/gnome.org/checkout/gobject-introspection/gir/ /home/dieterv/gnome.org/prefix/share/gir-1.0/  -name "*.gir" -exec xmllint --noout --nonet --schema /home/dieterv/gnome.org/checkout/gobject-introspection/giscanner/gir/gir.xsd '{}' \;
[WIP] docs: improve layout
!!! for testing only !!!
build: remove m4/as-compiler-flag.m4

no longer used since b2fd4f54883cd701a0c280655c93e20b04897ed2