[all] Remove dependencies on non-freestanding libc

This is the first of two rather big changes to clean up includes
throughout the project. In this commit, the implicit semi-dependency on
libc that bonnibel adds to every module is removed. Previously, I was
sloppy with includes of libc headers and include directory order. Now,
the freestanding headers from libc are split out into libc_free, and an
implicit real dependency is added onto this module, unless `no_libc` is
set to `True`. The full libc needs to be explicitly specified as a
dependency to be used.

Several things needed to change in order to do this:

- Many places use `memset` or `memcpy` that cannot depend on libc. The
  kernel has basic implementations of them itself for this reason. Now
  those functions are moved into the lower-level `j6/memutils.h`, and
  libc merely references them. Other modules are now free to reference
  those functions from libj6 instead.
- The kernel's `assert.h` was renamed kassert.h (matching its `kassert`
  function) so that the new `util/assert.h` can use `__has_include` to
  detect it and make sure the `assert` macro is usable in libutil code.
- Several implementation header files under `__libj6/` also moved under
  the new libc_free.
- A new `include_phase` property has been added to modules for Bonnibel,
  which can be "normal" (default) or "late" which uses `-idirafter`
  instead of `-I` for includes.
- Since `<utility>` and `<new>` are not freestanding, implementations of
  `remove_reference`, `forward`, `move`, and `swap` were added to the
  `util` namespace to replace those from `std`, and `util/new.h` was
  added to declare `operator new` and `operator delete`.

assets/build/base.yaml

@@ -9,7 +9,6 @@ variables:
 
   ccflags: [
     "-I${source_root}/src/include",
-    "-I${source_root}/src/include/x86_64",
     "-fcolor-diagnostics",
     "-U__STDCPP_THREADS__",
     "-D_LIBCPP_HAS_NO_THREADS",

assets/build/kernel-debug.yaml

@@ -35,8 +35,6 @@ variables:
     "-DPRINTF_ALIAS_STANDARD_FUNCTION_NAMES=1",
     "-DPRINTF_INCLUDE_CONFIG_H=1",
 
-    "-isystem${build_root}/include/libc",
-    "-isystem${source_root}/sysroot/include",
     "--sysroot='${source_root}/sysroot'" ]
 
 
@@ -46,7 +44,7 @@ variables:
     "-fno-exceptions",
     "-fno-rtti",
     "-nostdinc",
-    "-isystem${source_root}/sysroot/include/c++/v1" ]
+    ]
 
   ldflags: [
     "-g",

assets/build/rules.ninja

@@ -2,7 +2,7 @@
 
 rule compile.c
   command = $cc -MMD -MF $out.d $cflags $ccflags -o $out -c $in
-  description = Compiling $name
+  description = Compiling [$target]:$name
   depfile = $out.d
   deps = gcc
 
@@ -17,7 +17,7 @@ rule dump_c_run
 
 rule compile.cpp
   command = $cxx -MMD -MF $out.d $cxxflags $ccflags -o $out -c $in
-  description = Compiling $name
+  description = Compiling [$target]:$name
   depfile = $out.d
   deps = gcc
 
@@ -32,13 +32,13 @@ rule dump_cpp_run
 
 rule compile.s
   command = $nasm -o $out -felf64 -MD $out.d $asflags $in
-  description = Assembling $name
+  description = Assembling [$target]:$name
   depfile = $out.d
   deps = gcc
 
 rule parse.cog
   command = cog -o $out -d -D target=$target $cogflags $in
-  description = Parsing $name
+  description = Parsing [$target]:$name
 
 rule exe
   command = $ld $ldflags -o $out $in $libs
@@ -46,11 +46,11 @@ rule exe
 
 rule lib
   command = $ar qcs $out $in
-  description = Archiving $name
+  description = Archiving [$target]:$name
 
 rule cp
   command = cp $in $out
-  description = Copying $name
+  description = Copying [$target]:$name
 
 rule dump
   command = objdump -DSC -M intel $in > $out

assets/build/user-debug.yaml

@@ -21,15 +21,13 @@ variables:
     "-U__linux",
     "-U__linux__",
 
-    "-isystem${source_root}/sysroot/include",
-    "-isystem${build_root}/include/libc",
     "--sysroot='${source_root}/sysroot'" ]
 
 
   cxxflags: [
     "-fno-exceptions",
     "-fno-rtti",
-    "-isystem${source_root}/sysroot/include/c++/v1" ]
+    ]
 
   ldflags: [
     "-g",