build: build libuv.a and libuv.so in different dirs

Fixes #659.

Makefile

@@ -62,7 +62,7 @@ bench: test/run-benchmarks$(E)
 	$<
 
 clean: clean-platform
-	$(RM) -f src/*.o *.a test/run-tests$(E) test/run-benchmarks$(E)
+	$(RM) -f *.a *.so test/run-tests$(E) test/run-benchmarks$(E)
 
 distclean: distclean-platform
-	$(RM) -f src/*.o *.a test/run-tests$(E) test/run-benchmarks$(E)
+	$(RM) -f *.a *.so test/run-tests$(E) test/run-benchmarks$(E)

config-unix.mk

@@ -123,25 +123,32 @@ else
 RUNNER_LDFLAGS += -pthread
 endif
 
+OBJDIR := out
+ifeq ($(MAKECMDGOALS), test)
+	OBJDIR := $(OBJDIR)/test
+endif
+
+OBJS := $(addprefix $(OBJDIR)/,$(OBJS))
+
 libuv.a: $(OBJS)
 	$(AR) rcs $@ $^
 
 libuv.$(SOEXT):	override CFLAGS += -fPIC
 libuv.$(SOEXT):	$(OBJS)
 	$(CC) -shared -o $@ $^ $(LDFLAGS)
 
-src/%.o: src/%.c include/uv.h include/uv-private/uv-unix.h
+$(OBJDIR)/src/unix/%.o: src/unix/%.c include/uv.h include/uv-private/uv-unix.h src/unix/internal.h
+	@mkdir -p $(dir $@)
 	$(CC) $(CSTDFLAG) $(CPPFLAGS) $(CFLAGS) -c $< -o $@
 
-src/unix/%.o: src/unix/%.c include/uv.h include/uv-private/uv-unix.h src/unix/internal.h
+$(OBJDIR)/src/%.o: src/%.c include/uv.h include/uv-private/uv-unix.h
+	@mkdir -p $(dir $@)
 	$(CC) $(CSTDFLAG) $(CPPFLAGS) $(CFLAGS) -c $< -o $@
 
 clean-platform:
-	-rm -f src/unix/*.o
-	-rm -f src/unix/linux/*.o
+	-rm -rf $(OBJDIR)
 	-rm -rf test/run-tests.dSYM run-benchmarks.dSYM
 
 distclean-platform:
-	-rm -f src/unix/*.o
-	-rm -f src/unix/linux/*.o
+	-rm -rf $(OBJDIR)
 	-rm -rf test/run-tests.dSYM run-benchmarks.dSYM