b2/Makefile: add dependency generation (.d method)

b2/Makefile

@@ -9,6 +9,8 @@
 # (at your option) any later version.
 #
 
+SHELL = /bin/bash
+
 CFLAGS = -Wall $(shell pkg-config --cflags glib-2.0)
 SLOPPY = -Wno-unused -Wno-implicit-function-declaration
 OBJS = boom.o chr.o comp.o db.o eval.o param.o util.o lex.yy.o y.tab.o
@@ -61,6 +63,16 @@ y.tab.c y.tab.h: lang.y
 y.tab.o:	y.tab.c
 		$(CC) -c $(CFLAGS) $(SLOPPY) y.tab.c
 
+%.o:		%.c
+		$(CC) -c $(CFLAGS) $*.c -o $*.o
+		$(DEPEND) $*.c | \
+		  sed -e \
+		    '/^\(.*:\)\? */{p;s///;s/ *\\\?$$/ /;s/  */:\n/g;H;}' \
+		    -e '$${g;p;}' -e d >$*.d; \
+		  [ "$${PIPESTATUS[*]}" = "0 0" ] || { rm -f $*.d; exit 1; }
+
+-include $(OBJS:.o=.d)
+
 clean:
-		rm -f $(OBJS)
+		rm -f $(OBJS) $(OBJS:.o=.d)
 		rm -f lex.yy.c y.tab.c y.tab.h