build: Update and rename makefile.acorn to makefile.riscos

Co-authored-by: Cosmin Truta <ctruta@gmail.com>
Reviewed-by: John Bowler <jbowler@acm.org>
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
diff --git a/scripts/makefile.acorn b/scripts/makefile.riscos
similarity index 70%
rename from scripts/makefile.acorn
rename to scripts/makefile.riscos
index 00b8fb5..7baa148 100644
--- a/scripts/makefile.acorn
+++ b/scripts/makefile.riscos
@@ -1,14 +1,12 @@
 # Project:   libpng
 
+# Copyright (C) 2020 Cameron Cawley
+# Copyright (C) 1997 Tom Tanner
 
 # Toolflags:
-CCflags = -c -depend !Depend -IC:,Zlib: -g -throwback  -DRISCOS  -fnah
-C++flags = -c -depend !Depend -IC: -throwback
-Linkflags = -aif -c++ -o $@
-ObjAsmflags = -throwback -NoCache -depend !Depend
-CMHGflags =
+CCflags = -c -depend !Depend -IC:,C:zlib -g -throwback  -DRISCOS  -fnah -wz
+Linkflags = -aif -o $@
 LibFileflags = -c -l -o $@
-Squeezeflags = -o $@
 
 # Final targets:
 @.libpng-lib:   @.o.png @.o.pngerror @.o.pngrio @.o.pngwio @.o.pngmem \
@@ -27,14 +25,13 @@
 
 
 # User-editable dependencies:
-# (C) Copyright 1997 Tom Tanner
 Test: @.pngtest
-	<Prefix$Dir>.pngtest
-	@remove <Prefix$Dir>.pngtest
+	Run @.pngtest
+	@Remove @.pngtest
 
 #It would be nice if you could stop "make" listing from here on!
-@.pngtest:   @.o.pngtest @.libpng-lib C:o.Stubs Zlib:zlib_lib
-	Link $(Linkflags) @.o.pngtest @.libpng-lib C:o.Stubs Zlib:zlib_lib
+@.pngtest:   @.o.pngtest @.libpng-lib C:o.Stubs C:zlib.o.zlib
+	Link $(Linkflags) @.o.pngtest @.libpng-lib C:o.Stubs C:zlib.o.zlib
 
 .SUFFIXES: .o .mm .c
 
@@ -43,15 +40,15 @@
 .c.o:
 	cc $(ccflags) -o $@ $<
 
-# See scripts.mak.libpngconf for how to generate this:
-@.h.libpngconf: @.scripts.h.libpngconf
-	copy @.scripts.h.libpngconf $@
+# See scripts.pnglibconf/mak for how to generate this:
+@.h.pnglibconf: @.scripts.pnglibconf/h/prebuilt
+	Copy @.scripts.pnglibconf/h/prebuilt $@ ~CF~V
 
 # Static dependencies:
 @.o.png @.o.pngerror @.o.pngrio @.o.pngwio @.o.pngmem \
 @.o.pngpread @.o.pngset @.o.pngget @.o.pngread @.o.pngrtran \
 @.o.pngrutil @.o.pngtrans @.o.pngwrite @.o.pngwtran @.o.pngwutil \
-@.o.pngtest: @.h.libpngconf
+@.o.pngtest: @.h.pnglibconf
 
 
 # Dynamic dependencies: