further clean up OS differences in makefiles

No need for if() logic.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

mk/os-BSD.mk

@@ -3,4 +3,7 @@
 
 # Generic definitions
 
+PKG_PREFIX?=	/usr/local
+SFX=		.BSD.in
+
 LIBKVM?=	-lkvm

mk/os-Linux.mk

@@ -1,5 +1,8 @@
 # Copyright (c) 2008 Roy Marples <roy@marples.name>
 # Released under the 2-clause BSD license.
 
+SFX=		.Linux.in
+PKG_PREFIX?=	/usr
+
 CPPFLAGS+=	-D_BSD_SOURCE -D_XOPEN_SOURCE=600
 LIBDL=		-Wl,-Bdynamic -ldl

mk/os.mk

@@ -10,3 +10,5 @@ include ${MK}/os-${OS}.mk
 
 RC_LIB=		/$(LIBNAME)/rc
 
+SFX:=		${SFX_PFX}${SFX}
+.SUFFIXES:	${SFX}