Fix NetBSD version detection for `backtrace' in shells/fish.

Index: shells/fish/Makefile
===================================================================
RCS file: /cvsroot/pkgsrc/shells/fish/Makefile,v
retrieving revision 1.1
diff -p -u -r1.1 Makefile
--- shells/fish/Makefile	12 Dec 2012 13:21:42 -0000	1.1
+++ shells/fish/Makefile	23 Apr 2013 13:29:21 -0000
@@ -25,7 +25,7 @@ PKG_SHELL=		bin/fish
 .include "../../mk/bsd.prefs.mk"
 
 # backtrace() and backtrace_symbols were added in NetBSD-6.99.8
-.if !empty(MACHINE_PLATFORM:MNetBSD-*) && empty(MACHINE_PLATFORM:MNetBSD-[0-5].*) && empty(MACHINE_PLATFORM:MNetBSD-6.99.[0-7].*)
+.if !empty(MACHINE_PLATFORM:MNetBSD-*) && (empty(MACHINE_PLATFORM:MNetBSD-[0-6].*) || (!empty(MACHINE_PLATFORM:MNetBS-6.99.*) && empty(MACHINE_PLATFORM:MNetBSD-6.99.[0-7])))
 CPPFLAGS+=		-DHAVE_BACKTRACE
 CPPFLAGS+=		-DHAVE_BACKTRACE_SYMBOLS
 LDFLAGS+=		-lexecinfo