Variety of improvements

- Rename sources to distfiles for clarity.
- Per sys(a/c) distfiles to reduce rootfs.py processing and reduce RAM
  usage in sysa.
- Canonicalise early kaem mes/tcc files to kaem script conventions.
- Cleanup unused setup in python.

sysa/tcc-0.9.26/tcc-0.9.26.kaem

@@ -1,6 +1,6 @@
 #!/bin/sh
 
-# SPDX-FileCopyrightText: 2021 fosslinux <fosslinux@aussies.space>
+# SPDX-FileCopyrightText: 2021-22 fosslinux <fosslinux@aussies.space>
 #
 # SPDX-License-Identifier: GPL-3.0-or-later
 
@@ -20,15 +20,18 @@ TCC_PKG=tcc-0.9.26-1136-g5bba73cc
 MES_PKG=mes-0.23
 
 # Unpack
-mkdir src
-cp ${sources}/${TCC_TAR}.tar.gz src
+mkdir src build
+cp ${distfiles}/${TCC_TAR}.tar.gz src
+cp ${distfiles}/mes-0.23.tar.gz src
+
 cd src
 ungz ${TCC_TAR}.tar.gz
-untar ${TCC_TAR}.tar
-
-cp ${sources}/mes-0.23.tar.gz mes-0.23.tar.gz
 ungz mes-0.23.tar.gz
-untar mes-0.23.tar
+cd ..
+
+cd build
+untar ../src/${TCC_TAR}.tar
+untar ../src/mes-0.23.tar
 
 # Create config.h
 cd ${TCC_PKG}