synfig: bug fix and mark BROKEN-powerpc

- Fix wrong boundaries in a for loop that caused segfaults, from upstream
- On powerpc, synfig segfaults in multi-threaded mode, breaking
synfigstudio's build. Mark it BROKEN-powerpc to save time in bulks.

OK jca@

multimedia/synfig/Makefile

@@ -1,11 +1,13 @@
-# $OpenBSD: Makefile,v 1.30 2019/11/10 15:32:56 ajacoutot Exp $
+# $OpenBSD: Makefile,v 1.31 2020/04/23 04:55:46 cwen Exp $
+
+BROKEN-powerpc =	segfault in multi-threaded mode, synfigstudio can't be built
 
 COMMENT =		2D animation software
 
 V=			1.2.1
 DISTNAME =		synfig-$V
 API_V =			1.0
-REVISION =		4
+REVISION =		5
 
 SHARED_LIBS +=  synfig                    2.0 # 0.0
 

multimedia/synfig/patches/patch-src_synfig_filesystem_cpp

@@ -0,0 +1,17 @@
+$OpenBSD: patch-src_synfig_filesystem_cpp,v 1.1 2020/04/23 04:55:46 cwen Exp $
+
+Fix segfaults during the build of multimedia/synfigstudio, from
+https://github.com/synfig/synfig/issues/822
+
+Index: src/synfig/filesystem.cpp
+--- src/synfig/filesystem.cpp.orig
++++ src/synfig/filesystem.cpp
+@@ -181,7 +181,7 @@ String FileSystem::fix_slashes(const String &filename)
+ {
+ 	String fixed = etl::cleanup_path(filename);
+ 	if (fixed == ".") fixed = "";
+-	for(size_t i = 0; i < filename.size(); ++i)
++	for(size_t i = 0; i < fixed.size(); ++i)
+ 		if (fixed[i] == '\\') fixed[i] = '/';
+ 	return fixed;
+ }