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.

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