Change to recommanded m4/-style small files

m4/readline.m4

@@ -0,0 +1,47 @@
+dnl readline.m4
+dnl mdbtools specific version
+dnl TODO: Check if official version works then add serial
+AC_DEFUN([VL_LIB_READLINE], [
+  AC_CACHE_CHECK([for a readline compatible library],
+                 vl_cv_lib_readline, [
+    ORIG_LIBS="$LIBS"
+    for readline_lib in readline edit editline; do
+      for termcap_lib in "" termcap curses ncurses; do
+        TRY_LIB="-l$readline_lib"
+        if test -n "$termcap_lib"; then
+          TRY_LIB="$TRY_LIB -l$termcap_lib"
+        fi
+        LIBS="$ORIG_LIBS $TRY_LIB"
+        AC_TRY_LINK_FUNC(readline, vl_cv_lib_readline=yes)
+        if test "$vl_cv_lib_readline" = yes; then
+          break
+        fi
+      done
+      if test "$vl_cv_lib_readline" = yes; then
+        break
+      fi
+    done
+  ])
+
+  if test "$vl_cv_lib_readline" = yes; then
+    AC_DEFINE(HAVE_LIBREADLINE, 1,
+              [Define if you have a readline compatible library])
+    AC_CHECK_HEADERS(readline.h readline/readline.h)
+    AC_CACHE_CHECK([whether readline supports history],
+                   vl_cv_lib_readline_history, [
+      AC_TRY_LINK_FUNC(add_history, vl_cv_lib_readline_history=yes)
+    ])
+    if test "$vl_cv_lib_readline_history" = yes; then
+      AC_DEFINE(HAVE_READLINE_HISTORY, 1,
+                [Define if your readline library has \`add_history'])
+      AC_CHECK_HEADERS(history.h readline/history.h)
+    fi
+  fi
+  LIBS="$ORIG_LIBS"
+
+  LIBREADLINE=
+  if test "$vl_cv_lib_readline" = yes; then
+    LIBREADLINE="$TRY_LIB"
+  fi
+  AC_SUBST(LIBREADLINE)
+])dnl