[macppc] Unbreak audio/milkytracker

milkytracker is broken in the current macppc bulk:

> conv.c:78:51: error: invalid operand for instruction
> DEFINE_CLIPCONVERT_POWERPC(s8,f32, -128.0, 127.0, LFSUX, LBZ_STBUX)
> ^
> conv.c:65:16: note: expanded from macro 'LFSUX'
> #define LFSUX "1: lfsux f0,%1,%6 \n"
> ^
> <inline asm>:4:10: note: instantiated into assembly here
> 1: lfsux f0,5,6

I'm not proposing using `-fno-integrated-as' this time, because it
causes relocation errors. Since a fallback already exists, i think
we should use it.

I've reported the issue upstream as a PR, but i don't expect the
upstream fix to be as-is [0]. While here i've updated HOMEPAGE.

With the below diff it builds [1] and runs fine on macppc.

Comments/feedback are welcome,

Charlène.


[0] https://github.com/milkytracker/MilkyTracker/pull/210
[1] https://bin.charlenew.xyz/milkytracker.log


Index: Makefile
===================================================================
RCS file: /cvs/ports/audio/milkytracker/Makefile,v
retrieving revision 1.24
diff -u -p -u -p -r1.24 Makefile
--- Makefile 15 Apr 2020 13:31:42 -0000 1.24
+++ Makefile 28 Apr 2020 16:18:31 -0000
@@ -7,11 +7,11 @@ GH_PROJECT = MilkyTracker
GH_TAGNAME = v1.02.00

PKGNAME = ${DISTNAME:L}
-REVISION = 5
+REVISION = 6

CATEGORIES = audio

-HOMEPAGE = http://milkytracker.titandemo.org/
+HOMEPAGE = https://milkytracker.titandemo.org/

# GPLv3+
PERMIT_PACKAGE = Yes
Index: patches/patch-src_ppui_fastfill_h
===================================================================
RCS file: patches/patch-src_ppui_fastfill_h
diff -N patches/patch-src_ppui_fastfill_h
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ patches/patch-src_ppui_fastfill_h 28 Apr 2020 16:18:31 -0000
@@ -0,0 +1,26 @@
+$OpenBSD$
+
+powerpc fix for "error: invalid operand for instruction" in asm code
+see https://github.com/milkytracker/MilkyTracker/pull/210
+
+Index: src/ppui/fastfill.h
+--- src/ppui/fastfill.h.orig
++++ src/ppui/fastfill.h
+@@ -34,7 +34,7 @@ static __attribute__((noinline)) void fill_dword(pp_ui
+ static inline void fill_dword(pp_uint32* buff, pp_uint32 dw, pp_uint32 len)
+