Updated English Doc for NXP i.MX 8M Plus linux (#1265)

* fix missing 'fprintf' 'stderr' problem

* fix missing <cstdlib> header problem.

* updated en doc to compile for NXP i.MX 8M Plus linux.
Co-authored-by: NWang Feng <feng.wang1@hexagon.com>

doc/docs_en/source_compile/compile_timvx.md

@@ -10,17 +10,19 @@ Tengine Lite has supported to integrate with TIM-VX Library of Verisilicon to in
 
 For some special reasons, only supported on Khadas VIM3 or x86_64 simulator to work the following steps, currently.
 
-### Download Source code of TIM-VX 
+### Download Source code of TIM-VX
+
+TIM-VX is updated very frequently, and the latest compatible version is `68b5acb`.
 
 ```bash
 $ git clone https://github.com/VeriSilicon/TIM-VX.git
+$ cd TIM-VX && git checkout 68b5acb && cd ..
 ```
 
 ### Download Tengine Lite
 
 ```bash
 $ git clone https://github.com/OAID/Tengine.git tengine-lite
-$ cd tengine-lite
 ```
 
 ### 2.1 Prepare for x86_64 simulator platform
@@ -118,3 +120,41 @@ $ mkdir build && cd build
 $ cmake -DTENGINE_ENABLE_TIM_VX=ON ..
 $ make -j4
 ```
+
+
+### 2.3 Prepare for NXP i.MX 8M Plus Linux latform
+
+It is highly recommended to compile Tengine natively rather than cross-compiling.
+
+#### 2.4.1 Prepare 3rd-party library
+
+```bash
+wget -c https://github.com/VeriSilicon/TIM-VX/releases/download/v1.1.28/aarch64_S905D3_D312513_A294074_R311680_T312233_O312045.tgz && tar xvf aarch64_S905D3_D312513_A294074_R311680_T312233_O312045.tgz && mv aarch64_S905D3_D312513_A294074_R311680_T312233_O312045 prebuild-sdk-s905d3
+```
+
+#### 2.4.2 Prepare source files
+
+Suppose you have the following dependencies in a same directory:
+
+```
+.
+├── tengine-lite
+└── TIM-VX
+└── prebuild-sdk-s905d3
+```
+
+Then you can prepare the source files in the following way:
+
+```bash
+cd tengine-lite && mkdir -p ./source/device/tim-vx/ && /bin/cp -rf ../TIM-VX/include ./source/device/tim-vx/ && /bin/cp -rf ../TIM-VX/src ./source/device/tim-vx/ && mkdir -p ./3rdparty/tim-vx/include && mkdir -p ./3rdparty/tim-vx/lib/aarch64 && /bin/cp -rf ../prebuild-sdk-s905d3/include/* ./3rdparty/tim-vx/include/
+```
+
+#### 2.4.3 Build Tengine
+
+
+```bash
+mkdir -p build && cd ./build && cmake -DTENGINE_ENABLE_TIM_VX=ON .. && make -j4 VERBOSE=1 && make install
+```
+
+You will find `libengine-lite.so` from the install directory. And example applications are possible to run.
+

tools/save_graph/tm2_op_save.hpp

@@ -2,6 +2,7 @@
 #define __TM2_OP_SAVE_HPP__
 
 #include <functional>
+#include <cstdlib>
 extern "C" {
 #include "utility/vector.h"
 #include "serializer/tmfile/tm2_format.h"