Removed support of pngprefs.h from makefiles.

It is no longer used since the MMX support was removed.
diff --git a/scripts/makefile.openbsd b/scripts/makefile.openbsd
index e99fc2a..2d7dc54 100644
--- a/scripts/makefile.openbsd
+++ b/scripts/makefile.openbsd
@@ -1,6 +1,6 @@
 # makefile for libpng
 # Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
-# Copyright (C) 2006 Glenn Randers-Pehrson
+# Copyright (C) 2007-2008 Glenn Randers-Pehrson
 # For conditions of distribution and use, see copyright notice in png.h
 
 PREFIX?= /usr/local
@@ -11,21 +11,15 @@
 SHLIB_MINOR=	1.4.0beta57
 
 LIB=	png
-SRCS=	png.c pngerror.c pnggccrd.c pngget.c pngmem.c pngpread.c \
+SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \
 	pngread.c pngrio.c pngrtran.c pngrutil.c pngset.c pngtrans.c \
 	pngwio.c pngwrite.c pngwtran.c pngwutil.c
 
-HDRS=	png.h pngconf.h pngpriv.h pngdefs.h
+HDRS=	png.h pngconf.h
 
 CFLAGS+= -W -Wall
 CPPFLAGS+= -I${.CURDIR}
 
-all: pngconf.h pngdefs.h
-
-pngdefs.h:
-	echo "/* pngdefs.h was built by makefile.openbsd */" > pngdefs.h
-	echo "#define PNG_NO_ASSEMBLER_CODE" >> pngdefs.h
-
 NOPROFILE= Yes
 
 CLEANFILES+= pngtest.o pngtest
@@ -68,7 +62,6 @@
 	@rm -f ${DESTDIR}${LIBDIR}/debug/libpng.a
 	@rm -f ${DESTDIR}${PREFIX}/include/png.h
 	@rm -f ${DESTDIR}${PREFIX}/include/pngconf.h
-	@rm -f ${DESTDIR}${PREFIX}/include/pngdefs.h
 	@rmdir ${DESTDIR}${LIBDIR}/debug 2>/dev/null || true
 	${INSTALL} ${INSTALL_COPY} -o ${SHAREOWN} -g ${SHAREGRP} \
 		-m ${NONBINMODE} ${HDRS} ${DESTDIR}${PREFIX}/include/libpng