Re-add support for NetBSD/powerpc.

This time submitted upstream as well, ref.
python-greenlet/greenlet#402

devel/py-greenlet/distinfo

@@ -1,5 +1,6 @@
-$NetBSD: distinfo,v 1.22 2024/01/12 13:19:13 adam Exp $
+$NetBSD: distinfo,v 1.23 2024/03/30 19:40:04 he Exp $
 
 BLAKE2s (greenlet-3.0.3.tar.gz) = deb3fab6adac6a39ba856b5e14c91062f17ad2c9d597759c42e445c2c122b69b
 SHA512 (greenlet-3.0.3.tar.gz) = 20d8818376a200332cbc2c85968317ddf828d2adf3fcc3c53623cd1504ec9a4e4e987e841bd2fe65e934e2b8a5e73a7205847526f0bd196e7afcdf3ae40e9d9b
 Size (greenlet-3.0.3.tar.gz) = 182013 bytes
+SHA1 (patch-src_greenlet_slp__platformselect.h) = acb783cc5d0bbf336d68c5c171b22049099bb00d

devel/py-greenlet/patches/patch-src_greenlet_slp__platformselect.h

@@ -0,0 +1,15 @@
+$NetBSD: patch-src_greenlet_slp__platformselect.h,v 1.3 2024/03/30 19:40:05 he Exp $
+
+Add support for NetBSD/powerpc.
+
+--- src/greenlet/slp_platformselect.h.orig	2023-12-21 21:57:40.000000000 +0000
++++ src/greenlet/slp_platformselect.h
+@@ -27,6 +27,8 @@ extern "C" {
+ # include "platform/switch_ppc64_aix.h" /* gcc on AIX/PowerPC 64-bit */
+ #elif defined(__GNUC__) && defined(_ARCH_PPC) && defined(_AIX)
+ # include "platform/switch_ppc_aix.h" /* gcc on AIX/PowerPC */
++#elif defined(__GNUC__) && defined(__powerpc__) && defined(__NetBSD__)
++#include "platform/switch_ppc_unix.h" /* gcc on NetBSD/powerpc */
+ #elif defined(__GNUC__) && defined(sparc)
+ # include "platform/switch_sparc_sun_gcc.h" /* SunOS sparc with gcc */
+ #elif defined(__SUNPRO_C) && defined(sparc) && defined(sun)