Always use Unix-style forward slashes (/) in build files

resources/jni/Android.mk

@@ -2,5 +2,5 @@ LOCAL_PATH := $(call my-dir)/../..
 include $(CLEAR_VARS)
 LOCAL_CFLAGS    := -std=c99 -O2 -W -Wall -pthread -pipe $(COPT)
 LOCAL_MODULE    := civetweb
-LOCAL_SRC_FILES := src\main.c src\civetweb.c
+LOCAL_SRC_FILES := src/main.c src/civetweb.c
 include $(BUILD_EXECUTABLE)