layout: restructure into src/ tests/ android/ scripts/ tools/

- extension/src/{port,platform,codepage} -> src/; native_render -> src/host
  (+ dxt, shaders/); libgr2 -> src/gr2; extension/third_party -> third_party
- extension/tests -> tests/port, libgr2/tests -> tests/gr2
- android-native -> android (build.sh, push-client.sh moved in)
- script -> scripts; tools/40250 -> tools/server; oracle -> tools/granny-oracle;
  perf tools -> tools/perf
- all build trees under build/ (native, release, android, port-gate)
- xrender:: CMake aliases -> mt::; port-map ledger impl paths rewritten

No code changes. ctest 15/15, port_gate macos+android PASS, port_map check 0 errors.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

third_party/cpython-2.7.18/RISCOS/Python/dynload_riscos.c

@@ -0,0 +1,63 @@
+/***********************************************************
+Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,
+The Netherlands.
+
+                        All Rights Reserved
+
+Permission to use, copy, modify, and distribute this software and its
+documentation for any purpose and without fee is hereby granted,
+provided that the above copyright notice appear in all copies and that
+both that copyright notice and this permission notice appear in
+supporting documentation, and that the names of Stichting Mathematisch
+Centrum or CWI or Corporation for National Research Initiatives or
+CNRI not be used in advertising or publicity pertaining to
+distribution of the software without specific, written prior
+permission.
+
+While CWI is the initial source for this software, a modified version
+is made available by the Corporation for National Research Initiatives
+(CNRI) at the Internet address ftp://ftp.python.org.
+
+STICHTING MATHEMATISCH CENTRUM AND CNRI DISCLAIM ALL WARRANTIES WITH
+REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH
+CENTRUM OR CNRI BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
+DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+PERFORMANCE OF THIS SOFTWARE.
+
+******************************************************************/
+
+/* This module provides the necessary stubs for when dynamic loading is
+   not present. */
+
+#include "Python.h"
+#include "importdl.h"
+
+#include "dlk.h"
+
+
+const struct filedescr _PyImport_DynLoadFiletab[] = {
+    {"/pyd", "rb", C_EXTENSION},
+    {0, 0}
+};
+
+void dynload_init_dummy()
+{
+}
+
+dl_funcptr _PyImport_GetDynLoadFunc(const char *fqname, const char *shortname,
+                                    char *pathname, FILE *fp)
+{
+    int err;
+    char errstr[256];
+    void (*init_function)(void);
+
+    err = dlk_load_no_init(pathname, &init_function);
+    if (err) {
+        PyOS_snprintf(errstr, sizeof(errstr), "dlk failure %d", err);
+        PyErr_SetString(PyExc_ImportError, errstr);
+    }
+    return init_function;
+}

third_party/cpython-2.7.18/RISCOS/Python/getcwd_riscos.c

@@ -0,0 +1,5 @@
+char *getcwd(char *buf, int size)
+{
+  buf[0] = '\0';
+  return buf;
+}