Adding an API for developing Magic tools as plug-ins. (e.g., '.so'

shared objects under Linux)
Ported (most of) 'Negative' magic tool to Magic tool plug-in system.

magic/Makefile

@@ -0,0 +1,35 @@
+# Makefile for magic plugins
+
+SDL_CFLAGS=$(shell sdl-config --cflags)
+CFLAGS=-g -Wall $(SDL_CFLAGS) -DDATA_PREFIX=\"$(DATA_PREFIX)\"
+#-fPIC ?
+
+all:	negative.so
+
+clean:
+	@echo
+	@echo "Cleaning up the Magic plug-ins directory ($(PWD))"
+	@-rm -f *.so
+	@-rm -f obj/*
+
+
+# Negative tool
+# ------------------------------------------------------------------------
+
+negative.so:	obj obj/negative.o obj/magic_helpers.o
+	@echo "Linking Negative magic tool"
+	@$(CC) -shared -o negative.so obj/negative.o obj/magic_helpers.o
+
+obj/negative.o:	src/negative.c src/magic_helpers.h
+	@echo "Compiling Negative magic tool"
+	@$(CC) $(CFLAGS) src/negative.c -c -o obj/negative.o
+
+
+
+obj/magic_helpers.o:	src/magic_helpers.c src/magic_helpers.h
+	@echo "Compiling Magic tool helper routines"
+	@$(CC) $(CFLAGS) src/magic_helpers.c -c -o obj/magic_helpers.o
+
+obj:
+	@-mkdir obj
+