build-systems: remove autotools and Android.mk

Remove autotools and Android.mk support. This clauses less friction
when adding new tools.

Link: https://github.com/linux-can/can-utils/issues/526

.gitignore

@@ -1,30 +1,9 @@
 *~
 *.o
-*.lo
-*.la
-.deps
-.libs
 .ccls-cache
 compile_commands.json
-
-configure
-libtool
-GNUmakefile
-GNUmakefile.in
-
-/aclocal.m4
-/autom4te.cache/
-/calc-bit-timing/.dirstamp
-/config.log
-/config.status
-/config/autoconf/
-/config/m4/libtool.m4
-/config/m4/ltoptions.m4
-/config/m4/ltsugar.m4
-/config/m4/ltversion.m4
-/config/m4/lt~obsolete.m4
-/isobusfs/.dirstamp
-/mcp251xfd/.dirstamp
+tags
+/build
 
 /asc2log
 /bcmserver
@@ -59,8 +38,3 @@ GNUmakefile.in
 /slcand
 /slcanpty
 /testj1939
-
-/can-utils-*.tar.bz2
-/can-utils-*.tar.gz
-
-tags