make.bat: only configure once

make.bat

@@ -125,15 +125,18 @@ if NOT EXIST %BUILD_DIR%\nul (
 	mkdir %BUILD_DIR%
 )
 
-cmake ^
+REM Only configure on first run
+if NOT EXIST %BUILD_DIR%\Blender.sln (
+	cmake ^
 		%BUILD_CMAKE_ARGS% ^
 		-H%BLENDER_DIR% ^
 		-B%BUILD_DIR% ^
 		%BUILD_CMAKE_ARGS%
 
-if %ERRORLEVEL% NEQ 0 (
+	if %ERRORLEVEL% NEQ 0 (
 		echo "Configuration Failed"
 		goto EOF
+	)
 )
 
 msbuild ^