meta: replace cmake mono-build system with a custom build co-ordinator

every system component now has its own self-contained build system, and a
seed file describing the component and its build system and dependencies.

a new tool, meadow, collects and uses these seed files to build the
components into a full system. meadow also manages the target system root
and a host prefix where toolchain tools are installed to.

the build system has also been updated to use a new $ARCH-rosetta-gcc
compiler, and the patches files necessary to build it have been
added to toolchain/cross-compiler.

programs/CMakeLists.txt

@@ -3,6 +3,7 @@ file(GLOB items *)
 set(bshell_interactive 0)
 set(bshell_verbose 0)
 set(bshell_enable_floating_point 0)
+set(bshell_enable_native_commands 0)
 
 foreach(item ${items})
 	if (NOT IS_DIRECTORY ${item})

programs/external/bshell.seed

@@ -0,0 +1,18 @@
+[seed]
+name = 'bshell'
+
+[dependency]
+seeds = [
+	'libfx',
+]
+
+[build]
+build_system = 'cmake'
+source_dir = 'programs/bshell'
+configure_args = [
+	'-Dbshell_interactive=FALSE',
+	'-Dbshell_enable_native_commands=FALSE',
+	'-Dbshell_enable_floating_point=FALSE',
+]
+
+# vim: ft=toml