Autoconf generates several files in root folder of the project. Keep the root folder cleaner by specifying subfolder 'build-aux'. Align .gitignore accordingly. Signed-off-by: R. Diez <rdiezmail-openocd@yahoo.de> Change-Id: Ied87faba495d9eeb8f98e78c2e2b7e7e596febfb Reviewed-on: http://openocd.zylin.com/6236 Tested-by: jenkins Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>jim