Perform build and magnum tuning

Building o//third_party/python now takes 5 seconds on my PC

This change works towards modifying Python to use runtime dispatching
when appropriate. For example, when loading the magnums in the socket
module, it's a good idea to check if the magnum is zero, because that
means the local system platform doesn't support it.

third_party/python/Objects/stringlib/asciilib.inc

@@ -0,0 +1,31 @@
+/* clang-format off */
+/* clang-format off */
+/* this is sort of a hack.  there's at least one place (formatting
+   floats) where some stringlib code takes a different path if it's
+   compiled as unicode. */
+#define STRINGLIB_IS_UNICODE     1
+
+#define FASTSEARCH               asciilib_fastsearch
+#define STRINGLIB(F)             asciilib_##F
+#define STRINGLIB_OBJECT         PyUnicodeObject
+#define STRINGLIB_SIZEOF_CHAR    1
+#define STRINGLIB_MAX_CHAR       0x7Fu
+#define STRINGLIB_CHAR           Py_UCS1
+#define STRINGLIB_TYPE_NAME      "unicode"
+#define STRINGLIB_PARSE_CODE     "U"
+#define STRINGLIB_EMPTY          unicode_empty
+#define STRINGLIB_ISSPACE        Py_UNICODE_ISSPACE
+#define STRINGLIB_ISLINEBREAK    BLOOM_LINEBREAK
+#define STRINGLIB_ISDECIMAL      Py_UNICODE_ISDECIMAL
+#define STRINGLIB_TODECIMAL      Py_UNICODE_TODECIMAL
+#define STRINGLIB_STR            PyUnicode_1BYTE_DATA
+#define STRINGLIB_LEN            PyUnicode_GET_LENGTH
+#define STRINGLIB_NEW(STR,LEN)   _PyUnicode_FromASCII((char*)(STR),(LEN))
+#define STRINGLIB_CHECK          PyUnicode_Check
+#define STRINGLIB_CHECK_EXACT    PyUnicode_CheckExact
+
+#define STRINGLIB_TOSTR          PyObject_Str
+#define STRINGLIB_TOASCII        PyObject_ASCII
+
+#define _Py_InsertThousandsGrouping _PyUnicode_ascii_InsertThousandsGrouping
+