Log Message:
Update to version 4.2.2.  Support DESTDIR installation.  Add option
to build a "fat" binary on (${MACHINE_ARCH} == "i386" \ 
&& ${OPSYS} != "Darwin").
This isn't enabled by default now, but it might be useful for build builds,
as it uses cpuid at runtime to choose the most appropriate assembler code.
Insofar as I can tell, no BUILDLINK_A[BP]I_DEPENDS bump is necessary.

NOTE: Support for Darwin-*-i386 and Darwin-*-x86_64 has been improved,
see below.  Thus, I recommend that we test building the assembler code
on Darwin at some point.

Changes between GMP version 4.2.1 and 4.2.2:
	* License is now LGPL version 3.
Bugs:
	* Shared library numbers corrected for libcxx.
	* Fixed serious bug in gmpxx.h where a=a+b*c would generate garbage.
	  Note that this only affects C++ programs.
	* Fix crash in mpz_set_d for arguments with large negative exponent.
	* Fix 32-bit ABI bug with Itanium assembly for popcount and hamdist.
	* Fix assembly syntax problem for powerpc-ibm-aix with AIX
	  native assembler.
	* Fix problems with x86 --enable-fat, where the compiler where told to
	  generate code for the build machine, not plain i386 code as it should.
	* Improved recognition of powerpc systems wrt Altivec/VMX capability.
	* Misc minor fixes, mainly workarounds for compiler/assembler bugs.
Speedups:
	* "Core 2" and Pentium 4 processors, running in 64-bit mode will get a
	  slight boost as they are now specifically recognized.
Features:
	* New support for x86_64-solaris
	* New, rudimentary support for x86-apple-darwin and x86_64-apple-darwin.
	  (Please see http://gmplib.org/macos.html for more information.)