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/Modules/python.c

@@ -0,0 +1,21 @@
+/* Minimal main program -- everything is loaded from the library */
+
+#include "Python.h"
+
+#ifdef __FreeBSD__
+#include <fenv.h>
+#endif
+
+int
+main(int argc, char **argv)
+{
+	/* 754 requires that FP exceptions run in "no stop" mode by default,
+	 * and until C vendors implement C99's ways to control FP exceptions,
+	 * Python requires non-stop mode.  Alas, some platforms enable FP
+	 * exceptions by default.  Here we disable them.
+	 */
+#ifdef __FreeBSD__
+	fedisableexcept(FE_OVERFLOW);
+#endif
+	return Py_Main(argc, argv);
+}