add FetchContent installation method description to README

Author: bachue

docs/README.md

@@ -68,6 +68,24 @@ C-SDK 使用 [cURL](http://curl.haxx.se/) 进行网络相关操作。无论是
 
 如果在项目构建过程中出现环境相关的编译错误和链接错误，请确认这些选项是否都已经正确配置，以及所依赖的库是否都已经正确的安装。
 
+#### 通过 CMake 编译
+
+如果想在 CMake 项目里使用 C-SDK，可以直接在 CMake 里导入 C-SDK：
+
+```cmake
+INCLUDE(FetchContent)
+FetchContent_Declare(
+  qiniu
+  GIT_REPOSITORY https://github.com/qiniu/c-sdk.git
+  GIT_TAG v7.8.0
+)
+FetchContent_MakeAvailable(qiniu)
+FIND_PACKAGE(CURL REQUIRED)
+FIND_PACKAGE(OpenSSL REQUIRED)
+TARGET_LINK_LIBRARIES(${PROJECT_NAME} PRIVATE qiniu m)
+TARGET_LINK_LIBRARIES(${PROJECT_NAME} PRIVATE ${CURL_LIBRARIES})
+TARGET_LINK_LIBRARIES(${PROJECT_NAME} PRIVATE ${OPENSSL_LIBRARIES})
+```
 
 <a name="appkey"></a>
 
@@ -169,7 +187,7 @@ typedef struct _Qiniu_Error {
 typedef struct _Qiniu_RS_StatRet {
 	const char* hash;
 	const char* mimeType;
-	Qiniu_Int64 fsize;	
+	Qiniu_Int64 fsize;
 	Qiniu_Int64 putTime;
 } Qiniu_RS_StatRet;
 ```
@@ -427,7 +445,7 @@ void stat(Qiniu_Client* client, const char* bucket, const char* key)
 typedef struct _Qiniu_RS_StatRet {
 	const char* hash;
 	const char* mimeType;
-	Qiniu_Int64 fsize;	
+	Qiniu_Int64 fsize;
 	Qiniu_Int64 putTime;
 } Qiniu_RS_StatRet;
 ```
@@ -456,8 +474,8 @@ void delete(Qiniu_Client* client, const char* bucket, const char* key)
 复制和移动操作，需要指定源路径和目标路径。
 
 ```{c}
-void copy(Qiniu_Client* client, 
-	const char* bucketSrc, const char* keySrc, 
+void copy(Qiniu_Client* client,
+	const char* bucketSrc, const char* keySrc,
 	const char* bucketDest, const char* keyDest)
 {
 	Qiniu_Error err = Qiniu_RS_Copy(client, bucketSrc, keySrc, bucketDest, keyDest);
@@ -470,8 +488,8 @@ void copy(Qiniu_Client* client,
 ```
 
 ```{c}
-void move(Qiniu_Client* client, 
-	const char* bucketSrc, const char* keySrc, 
+void move(Qiniu_Client* client,
+	const char* bucketSrc, const char* keySrc,
 	const char* bucketDest, const char* keyDest)
 {
 	Qiniu_Error err = Qiniu_RS_Move(client, bucketSrc, keySrc, bucketDest, keyDest);
@@ -494,7 +512,7 @@ void move(Qiniu_Client* client,
 调用`Qiniu_RS_BatchStat`可以批量查看多个文件的属性信息。
 
 ```{c}
-void batchStat(Qiniu_Client* client, 
+void batchStat(Qiniu_Client* client,
 	Qiniu_RS_EntryPath* entries, Qiniu_ItemCount entryCount)
 {
 	Qiniu_RS_BatchStatRet* rets = calloc(entryCount, sizeof(Qiniu_RS_BatchStatRet));
@@ -551,7 +569,7 @@ typedef struct _Qiniu_RS_BatchStatRet {
 typedef struct _Qiniu_RS_StatRet {
 	const char* hash;
 	const char* mimeType;
-	Qiniu_Int64 fsize;	
+	Qiniu_Int64 fsize;
 	Qiniu_Int64 putTime;
 } Qiniu_RS_StatRet;
 ```
@@ -563,7 +581,7 @@ typedef struct _Qiniu_RS_StatRet {
 调用`Qiniu_RS_BatchDelete`可以批量删除多个文件。
 
 ```{c}
-void batchDelete(Qiniu_Client* client, 
+void batchDelete(Qiniu_Client* client,
 	Qiniu_RS_EntryPath* entries, Qiniu_ItemCount entryCount)
 {
 	Qiniu_RS_BatchItemRet* rets = calloc(entryCount, sizeof(Qiniu_RS_BatchItemRet));
@@ -604,7 +622,7 @@ typedef struct _Qiniu_RS_BatchItemRet {
 调用`Qiniu_RS_BatchCopy`可以批量复制多个文件。
 
 ```{c}
-void batchCopy(Qiniu_Client* client, 
+void batchCopy(Qiniu_Client* client,
 	Qiniu_RS_EntryPathPair* entryPairs, Qiniu_ItemCount entryCount)
 {
 	Qiniu_RS_BatchItemRet* rets = calloc(entryCount, sizeof(Qiniu_RS_BatchItemRet));
@@ -644,7 +662,7 @@ typedef struct _Qiniu_RS_EntryPathPair {
 批量移动和批量复制很类似，唯一的区别就是调用`Qiniu_RS_BatchMove`。
 
 ```{c}
-void batchMove(Qiniu_Client* client, 
+void batchMove(Qiniu_Client* client,
 	Qiniu_RS_EntryPathPair* entryPairs, Qiniu_ItemCount entryCount)
 {
 	Qiniu_RS_BatchItemRet* rets = calloc(entryCount, sizeof(Qiniu_RS_BatchItemRet));