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.

toolchain/meadow/args.py

@@ -0,0 +1,42 @@
+class Args:
+    def __init__(self, argv):
+        self.__argv = argv
+
+
+    def get_positional(self, index):
+        if len(self.__argv) > index:
+            return self.__argv[index]
+        return None
+
+
+    def get_named(self, name, index, nr_args):
+        found_name = False
+        values = []
+
+        for s in self.__argv:
+            if found_name:
+                if nr_args > 0:
+                    nr_args -= 1
+                    values.append(s)
+                    continue
+                else:
+                    break
+
+            if s == '--{}'.format(name):
+                if index > 0:
+                    index -= 1
+                    continue
+
+                found_name = True
+                continue
+
+        if nr_args == 0:
+            return found_name
+
+        if nr_args > 0 or not found_name:
+            return None
+
+        if len(values) == 1:
+            return values[0]
+
+        return values