refactoring

- overlays/{linux,wine-osu}.nix -> packages/{linux-lava,wine-osu}/
- overlays/misc/ -> overlays/patches/
- overlays/misc/0001...patch -> packages/linux-lava/si...patch
- overlays/misc/wine/ -> packages/wine-osu/patches/
- flake.nix:
  - overlays are dynamically read from overlays/
  - define custom packages separately
- packages/*
  - now imported using callPackage

overlays/misc/startx.patch

@@ -1,26 +0,0 @@
-diff --git a/startx.cpp b/startx.cpp
-index 125c398..296b29f 100644
---- a/startx.cpp
-+++ b/startx.cpp
-@@ -47,10 +47,10 @@ XCOMM so export the new PATH just in case the user changes the shell
- export PATH
- #endif
- 
--userclientrc=$HOME/.xinitrc
-+userclientrc="${XINITRC:-$HOME/.xinitrc}"
- sysclientrc=XINITDIR/xinitrc
- 
--userserverrc=$HOME/.xserverrc
-+userserverrc="${XSERVERRC:-$HOME/.xserverrc}"
- sysserverrc=XINITDIR/xserverrc
- defaultclient=XTERM
- defaultserver=XSERVER
-@@ -270,7 +270,7 @@ if [ x"$enable_xauth" = x1 ] ; then
-     dummy=0
- 
-     XCOMM create a file with auth information for the server. ':0' is a dummy.
--    xserverauthfile=$HOME/.serverauth.$$
-+    xserverauthfile=$XAUTHORITY
-     trap "rm -f '$xserverauthfile'" HUP INT QUIT ILL TRAP KILL BUS TERM
-     xauth -q -f "$xserverauthfile" << EOF
- add :$dummy . $mcookie