Add configure script and proper install target

configure

@@ -0,0 +1,28 @@
+#!/bin/sh
+while test -n "$1"; do
+  case "$1" in
+  (--*=*)
+    val=${1#--}
+    name=${val%%=*}
+    val=${val#*=}
+    export "$(printf "%s\n" "$name"|tr '[:lower:]-' '[:upper:]_')=$val"
+    ;;
+  esac
+  shift
+done
+
+(
+  # Variables that the makefile uses and that are meant to be configurable
+  awk '/ \?=/ {print($1)}' Makefile
+  # Variables that GNU Make uses for the implicit rules
+  cat <<EOF
+CC
+CPPFLAGS
+CFLAGS
+LDFLAGS
+LOADLIBES
+LDLIBS
+EOF
+)|sort -u|while read varname; do
+  eval "test -n \"\${$varname+x}\" && echo \${varname}=\${$varname}"
+done|tee config.mak