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/xpcg/CMakeLists.txt

@@ -1,3 +1,9 @@
+cmake_minimum_required(VERSION 3.31)
+project(xpcg C)
+
+find_package(FX REQUIRED COMPONENTS
+	fx.runtime fx.collections fx.cmdline fx.serial fx.io fx.term)
+
 file(GLOB sources
 	*.c *.h
 	backend/c-mpc/*.c backend/c-mpc/*.h)
@@ -5,3 +11,10 @@ file(GLOB sources
 add_executable(xpcg ${sources})
 
 target_link_libraries(xpcg FX::Runtime FX::Collections FX::Cmdline FX::Io)
+install(TARGETS xpcg)
+
+set_target_properties(
+    xpcg
+    PROPERTIES
+    INSTALL_RPATH
+    "${CMAKE_INSTALL_RPATH};${CMAKE_INSTALL_PREFIX}/lib")