Create shared library

Shared library is now the default, use configure --enable-static to
build the static library.

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>

Makefile

@@ -12,13 +12,11 @@ $(MAIN_PATH)/options.o: Makefile
 
 M_OBJS	= $(addprefix $(MAIN_PATH)/,$(MAIN_OBJS))
 
-$(MAIN_PATH)/xmp: $(M_OBJS) $(LIB)
+$(MAIN_PATH)/xmp: $(M_OBJS)
 	@CMD='$(LD) -o $@ $(LDFLAGS) $(M_OBJS) -Llib -lxmp -lm -lasound'; \
 	if [ "$(V)" -gt 0 ]; then echo $$CMD; else echo LD $@ ; fi; \
 	eval $$CMD
 
-$(M_OBJS): $(LIB)
-
 install-xmp: $(MAIN_PATH)/xmp
 	@echo Installing xmp in $(DESTDIR)$(BINDIR)
 	@[ -d $(DESTDIR)$(BINDIR) ] || mkdir -p $(DESTDIR)$(BINDIR)