add .gitignore file

Signed-off-by: Luotao Fu <l.fu@pengutronix.de>

.gitignore

@@ -0,0 +1,29 @@
+libtool
+configure
+GNUmakefile
+GNUmakefile.in
+
+aclocal.m4
+config/libsocketcan-nl.pc
+config/m4/libtool.m4
+config/m4/ltoptions.m4
+config/m4/ltsugar.m4
+config/m4/ltversion.m4
+config/m4/lt~obsolete.m4
+include/libsocketcan-nl_config.h
+include/libsocketcan-nl_config.h.in
+include/stamp-h1
+
+config.log
+config.status
+config/autoconf/
+autom4te.cache/
+
+src/.libs/
+src/*.l*
+tests/.libs/
+tests/test
+
+*~
+*.o
+.deps/