Human-readable error if Git or Python are missing.

When user forgot to add git.exe or python to the PATH, there was a not
very helpful error message.
This improves the error with which tool is misssing and shows a link to
the espressif installer tool.

export.bat

@@ -5,6 +5,22 @@ if defined MSYSTEM (
     goto :eof
 )
 
+:: Missing requirements check
+set MISSING_REQUIREMENTS=
+python.exe --version >NUL 2>NUL
+if %errorlevel% neq 0 set "MISSING_REQUIREMENTS=  python &echo\"
+git.exe --version >NUL 2>NUL
+if %errorlevel% neq 0 set "MISSING_REQUIREMENTS=%MISSING_REQUIREMENTS%  git"
+
+if not "%MISSING_REQUIREMENTS%" == "" goto :error_missing_requirements
+
+set PREFIX=python.exe %IDF_PATH%
+DOSKEY idf.py=%PREFIX%\tools\idf.py $*
+DOSKEY esptool.py=%PREFIX%\components\esptool_py\esptool\esptool.py $*
+DOSKEY espefuse.py=%PREFIX%\components\esptool_py\esptool\espefuse.py $*
+DOSKEY otatool.py=%PREFIX%\components\app_update\otatool.py $*
+DOSKEY parttool.py=%PREFIX%\components\partition_table\parttool.py $*
+
 :: Infer IDF_PATH from script location
 set IDF_PATH=%~dp0
 set IDF_PATH=%IDF_PATH:~0,-1%
@@ -55,6 +71,17 @@ goto :end
     echo.
     goto :eof
 
+:error_missing_requirements
+    echo.
+    echo Error^: The following tools are not installed in your environment.
+    echo.
+    echo %MISSING_REQUIREMENTS%
+    echo.
+    echo Please use the Windows Tool installer for setting up your environment.
+    echo Download link: https://dl.espressif.com/dl/esp-idf/
+    echo For more details please visit our website: https://docs.espressif.com/projects/esp-idf/en/latest/esp32/get-started/windows-setup.html
+    goto :end
+
 :end
 
 :: Clean up
@@ -68,3 +95,4 @@ set IDF_TOOLS_PY_PATH=
 set IDF_TOOLS_JSON_PATH=
 set OLD_PATH=
 set PATH_ADDITIONS=
+set MISSING_REQUIREMENTS=

install.bat

@@ -4,6 +4,16 @@ if defined MSYSTEM (
 	echo   ./install.sh.
 	goto end
 )
+
+:: Missing requirements check
+set MISSING_REQUIREMENTS=
+python.exe --version >NUL 2>NUL
+if %errorlevel% neq 0 set "MISSING_REQUIREMENTS=  python &echo\"
+git.exe --version >NUL 2>NUL
+if %errorlevel% neq 0 set "MISSING_REQUIREMENTS=%MISSING_REQUIREMENTS%  git"
+
+if not "%MISSING_REQUIREMENTS%" == "" goto :error_missing_requirements
+
 :: Infer IDF_PATH from script location
 set IDF_PATH=%~dp0
 set IDF_PATH=%IDF_PATH:~0,-1%
@@ -18,5 +28,17 @@ if %errorlevel% neq 0 goto :end
 
 echo All done! You can now run:
 echo    export.bat
+goto :end
+
+:error_missing_requirements
+    echo.
+    echo Error^: The following tools are not installed in your environment.
+    echo.
+    echo %MISSING_REQUIREMENTS%
+    echo.
+    echo Please use the Windows Tool installer for setting up your environment.
+    echo Download link: https://dl.espressif.com/dl/esp-idf/
+    echo For more details please visit our website: https://docs.espressif.com/projects/esp-idf/en/latest/esp32/get-started/windows-setup.html
+    goto :end
 
 :end