build: update autogen

Bring new options from systemd and other projects.
diff --git a/bootstrap b/bootstrap
index d50dae9..c980f24 100755
--- a/bootstrap
+++ b/bootstrap
@@ -1,30 +1,64 @@
 #!/bin/sh
+
 set -e
 
+oldpwd=$(pwd)
+topdir=$(dirname $0)
+cd $topdir
+
 gtkdocize --docdir libkmod/docs || touch libkmod/docs/gtk-doc.make
-autoreconf --install --symlink
+autoreconf --force --install --symlink
 
 libdir() {
-	(cd "$1/$(gcc -print-multi-os-directory)"; pwd)
+        echo $(cd "$1/$(gcc -print-multi-os-directory)"; pwd)
 }
 
-args="--prefix=/usr \
+args="\
+--prefix=/usr \
 --sysconfdir=/etc \
---libdir=$(libdir /usr/lib)"
+--libdir=$(libdir /usr/lib) \
+"
+
+if [ -f "$topdir/.config.args" ]; then
+    args="$args $(cat $topdir/.config.args)"
+fi
+
+if [ ! -L /bin ]; then
+    args="$args \
+        --with-rootprefix= \
+        --with-rootlibdir=$(libdir /lib) \
+        "
+fi
+
+cd $oldpwd
 
 hackargs="--enable-debug --enable-python --with-xz --with-zlib"
 
-cat <<EOC
-
-----------------------------------------------------------------
-Initialized build system. For a common configuration please run:
-----------------------------------------------------------------
-
-./configure CFLAGS='-g -O2' $args
-
-If you are debugging or hacking on kmod, consider configuring
-like below:
-
-./configure CFLAGS="-g -O2" $args $hackargs
-
-EOC
+if [ "x$1" = "xc" ]; then
+        $topdir/configure CFLAGS='-g -O2' $args
+        make clean
+elif [ "x$1" = "xg" ]; then
+        $topdir/configure CFLAGS='-g -Og' $args
+        make clean
+elif [ "x$1" = "xl" ]; then
+        $topdir/configure CC=clang CXX=clang++ $args
+        make clean
+elif [ "x$1" = "xa" ]; then
+        $topdir/configure CFLAGS='-g -O2 -Wsuggest-attribute=pure -Wsuggest-attribute=const' $args
+        make clean
+elif [ "x$1" = "xs" ]; then
+        scan-build $topdir/configure CFLAGS='-g -O0 -std=gnu11' $args
+        scan-build make
+else
+        echo
+        echo "----------------------------------------------------------------"
+        echo "Initialized build system. For a common configuration please run:"
+        echo "----------------------------------------------------------------"
+        echo
+        echo "$topdir/configure CFLAGS='-g -O2' $args"
+        echo
+        echo If you are debugging or hacking on kmod, consider configuring
+        echo like below:
+        echo 
+        echo "$topdir/configure CFLAGS="-g -O2" $args $hackargs"
+fi