fix : apr_build error on linux and VS19

README.md

@@ -1,3 +1,5 @@
+[中文版本使用说明](<https://github.com/Livox-SDK/Livox-SDK/blob/master/README_CN.md>)
+
 # 1 Introduction
 
 Livox SDK is the software development kit designed for all Livox products. It is developed based on C/C++ following Livox SDK Communication Protocol, and provides easy-to-use C style API. With Livox SDK, users can quickly connect to Livox products and receive point cloud data. 
@@ -41,12 +43,29 @@ In the Livox SDK directory, run the following commands to compile the project:
 ```
 git clone https://github.com/Livox-SDK/Livox-SDK.git
 cd Livox-SDK
+```
+Install apr library by:
+
+```
 sudo ./third_party/apr/apr_build.sh
+```
+
+or by:
+
+```
+sudo apt install libapr1-dev
+```
+
+then
+
+```
 cd build && cmake ..
 make
 sudo make install
 ```
+
 ### 4.1.2 Windows 7/10
+
 #### Dependencies
 Livox SDK supports Visual Studio 2015/2017 and requires install [CMake 3.0.0+](https://cmake.org/) as dependencies.  
 

README_CN.md

@@ -42,12 +42,31 @@ sudo apt install cmake pkg-config
 ```
 git clone https://github.com/Livox-SDK/Livox-SDK.git
 cd Livox-SDK
+
+
+```
+安装 apr 库通过：
+
+```
 sudo ./third_party/apr/apr_build.sh
+```
+
+或者通过：
+
+```
+sudo apt install libapr1-dev
+```
+
+然后：
+
+```
 cd build && cmake ..
 make
 sudo make install
 ```
+
 ### 4.1.2 Windows 7/10
+
 #### 依赖
 Livox SDK 支持 Visual Studio 2015/2017，需要安装 [CMake 3.0.0+](https://cmake.org/) 依赖。
 

third_party/apr/apr_build.bat

@@ -50,6 +50,18 @@ if defined VS150COMNTOOLS (
 	call "%ProgramFiles(x86)%\Microsoft Visual Studio\2017\BuildTools\VC\Auxiliary\Build\vcvarsall.bat" %PLATFORM%
 )
 
+if defined VS160COMNTOOLS (
+	call "%VS160COMNTOOLS%..\..\VC\Auxiliary\Build\vcvarsall.bat" %PLATFORM%
+) else if exist "%ProgramFiles(x86)%\Microsoft Visual Studio\2019\Enterprise\VC\Auxiliary\Build\vcvarsall.bat" (
+	call "%ProgramFiles(x86)%\Microsoft Visual Studio\2019\Enterprise\VC\Auxiliary\Build\vcvarsall.bat" %PLATFORM%
+) else if exist "%ProgramFiles(x86)%\Microsoft Visual Studio\2019\Professional\VC\Auxiliary\Build\vcvarsall.bat" (
+	call "%ProgramFiles(x86)%\Microsoft Visual Studio\2019\Professional\VC\Auxiliary\Build\vcvarsall.bat" %PLATFORM%
+) else if exist "%ProgramFiles(x86)%\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvarsall.bat" (
+	call "%ProgramFiles(x86)%\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvarsall.bat" %PLATFORM%
+) else if exist "%ProgramFiles(x86)%\Microsoft Visual Studio\2019\BuildTools\VC\Auxiliary\Build\vcvarsall.bat" (
+	call "%ProgramFiles(x86)%\Microsoft Visual Studio\2019\BuildTools\VC\Auxiliary\Build\vcvarsall.bat" %PLATFORM%
+) 
+
 echo start to build.
 
 pushd %~dp0apr-1.6.5

third_party/apr/apr_build.sh

@@ -59,4 +59,8 @@ make install
 
 popd
 
+if [ ! -d "/usr/local/lib/pkgconfig" ]; then
+	mkdir /usr/local/lib/pkgconfig
+fi
+
 cp /usr/local/apr/lib/pkgconfig/apr-1.pc /usr/local/lib/pkgconfig/