Merge C version of decimal into py3k.

Modules/_decimal/README.txt

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Modules/_decimal/README.txt	Sat Mar 10 18:12:20 2012 +0100
@@ -0,0 +1,46 @@
+
+
+About
+=====
+
+_decimal.c is a wrapper for the libmpdec library. libmpdec is a fast C
+library for correctly-rounded arbitrary precision decimal floating point
+arithmetic. It is a complete implementation of Mike Cowlishaw/IBM's
+General Decimal Arithmetic Specification.
+
+
+Build process for the module
+============================
+
+As usual, the build process for decimal.so is driven by setup.py in the top
+level directory. setup.py autodetects the following build configurations:
+
+   1) x64         - 64-bit Python, x86_64 processor (AMD, Intel)
+
+   2) uint128     - 64-bit Python, compiler provides __uint128_t (gcc)
+
+   3) ansi64      - 64-bit Python, ANSI C
+
+   4) ppro        - 32-bit Python, x86 CPU, PentiumPro or later
+
+   5) ansi32      - 32-bit Python, ANSI C
+
+   6) ansi-legacy - 32-bit Python, compiler without uint64_t
+
+   7) universal   - Mac OS only (multi-arch)
+
+
+It is possible to override autodetection by exporting:
+
+   PYTHON_DECIMAL_WITH_MACHINE=value, where value is one of the above options.
+
+
+NOTE
+====
+ 
+decimal.so is not built from a static libmpdec.a since doing so led to
+failures on AIX (user report) and Windows (mixing static and dynamic CRTs
+causes locale problems and more).
+
+
+