Disable 8139too driver by default

From now on, if you want 8139too support you must explicitly pass
`--enable-8139too` to `./configure`.

.gitlab-ci.yml

@@ -12,7 +12,7 @@ build:
 
     script:
         - ./bootstrap
-        - ./configure --with-linux-dir=/usr/src/linux-obj/$(uname -i)/default --disable-8139too --enable-tty --with-devices=2 --enable-ccat
+        - ./configure --with-linux-dir=/usr/src/linux-obj/$(uname -i)/default --enable-tty --with-devices=2 --enable-ccat
         - make -j8 all modules
         - make DISTCHECK_CONFIGURE_FLAGS="--with-linux-dir=/usr/src/linux-obj/$(uname -i)/default" distcheck
 
@@ -54,7 +54,7 @@ doxygen:
         GIT_SUBMODULE_STRATEGY: recursive
     script:
         - ./bootstrap
-        - ./configure --with-linux-dir=/usr/src/linux-obj/$(uname -i)/default --disable-8139too --enable-tty --with-devices=2 --enable-ccat
+        - ./configure --with-linux-dir=/usr/src/linux-obj/$(uname -i)/default --enable-tty --with-devices=2 --enable-ccat
         - make doc
         - mv doxygen-output/html/ html/
     artifacts:

Makefile.am

@@ -30,7 +30,6 @@ include $(top_srcdir)/Makefile.kbuild
 ACLOCAL_AMFLAGS = -I m4
 
 AM_DISTCHECK_CONFIGURE_FLAGS = \
-	--disable-8139too \
 	--with-systemdsystemunitdir=$$dc_install_base/$(systemdsystemunitdir)
 
 SUBDIRS = \

configure.ac

@@ -209,7 +209,7 @@ AC_ARG_ENABLE([8139too],
                 ;;
         esac
     ],
-    [enable8139too=$enablekernel]
+    [enable8139too=0] # disabled by default
 )
 
 AM_CONDITIONAL(ENABLE_8139TOO, test "x$enable8139too" = "x1")