Ignore build-aux/config.guess, build-aux/config.sub

These currently aren't installed by `autoreconf --install`, but ignore
them anyway as a defensive measure.

Author: rhansen

.gitignore

@@ -7,6 +7,8 @@ release
 /Makefile.in
 /aclocal.m4
 /autom4te.cache/
+/build-aux/config.guess
+/build-aux/config.sub
 /build-aux/install-sh
 /build-aux/missing
 /build-aux/tap-driver.sh

autogen

@@ -13,6 +13,8 @@ try mkdir -p build-aux/m4
 # Remove the files to truly force them to be updated.
 try rm -f \
     aclocal.m4 \
+    build-aux/config.guess \
+    build-aux/config.sub \
     build-aux/install-sh \
     build-aux/missing \
     build-aux/tap-driver.sh \