BUG#25530 --with-readline fails with commercial source packages

BUILD/SETUP.sh:
  BUG#25530 --with-readline fails with commercial source packages
  
  The compile-* scripts should not use --with-readline explicitly when no readline is present.
configure.in:
  BUG#25530 --with-readline fails with commercial source packages
  
  Configuring --with-readline should fail when libreadline is not bundled.
  A system libreadline is only used when there is a bundled libreadline too, so the commercial source code isn't linked with GPL libreadline by accident.

BUILD/SETUP.sh

@@ -84,7 +84,16 @@ debug_extra_cflags="-O1 -Wuninitialized"
 base_cxxflags="-felide-constructors -fno-exceptions -fno-rtti"
 amd64_cxxflags=""				# If dropping '--with-big-tables', add here  "-DBIG_TABLES"
 
-base_configs="$prefix_configs --enable-assembler --with-extra-charsets=complex --enable-thread-safe-client --with-readline --with-big-tables"
+base_configs="$prefix_configs --enable-assembler --with-extra-charsets=complex --enable-thread-safe-client --with-big-tables"
+
+if test -d "$path/../cmd-line-utils/readline"
+then
+    base_configs="$base_configs --with-readline"
+elif test -d "$path/../cmd-line-utils/libedit"
+then
+    base_configs="$base_configs --with-libedit"
+fi
+
 static_link="--with-mysqld-ldflags=-all-static --with-client-ldflags=-all-static"
 amd64_configs=""
 alpha_configs=""	# Not used yet

configure.in

@@ -2439,6 +2439,7 @@ readline_basedir=""
 readline_dir=""
 readline_h_ln_cmd=""
 readline_link=""
+want_to_use_readline="no"
 
 if expr "$SYSTEM_TYPE" : ".*netware.*" > /dev/null; then
     # For NetWare, do not need readline
@@ -2463,6 +2464,7 @@ then
     readline_link="\$(top_builddir)/cmd-line-utils/readline/libreadline.a"
     readline_h_ln_cmd="\$(LN) -s \$(top_srcdir)/cmd-line-utils/readline readline"
     compile_readline=yes
+    want_to_use_readline="yes"
     AC_DEFINE_UNQUOTED(USE_NEW_READLINE_INTERFACE, 1)
 else
     # Use system readline library
@@ -2472,10 +2474,12 @@ else
     MYSQL_CHECK_NEW_RL_INTERFACE
     MYSQL_CHECK_READLINE_DECLARES_HIST_ENTRY
     AC_LANG_RESTORE
-    if [test "$mysql_cv_new_rl_interface" = "yes"]
+    if [test "$mysql_cv_new_rl_interface" = "yes"] && [test -d "./cmd-line-utils/readline"]
     then
-        # Use the new readline interface
+        # Use the new readline interface, but only if the package includes a bundled libreadline
+        # this way we avoid linking commercial source with GPL readline
         readline_link="-lreadline"
+        want_to_use_readline="yes"
     elif [test "$mysql_cv_libedit_interface" = "yes"]; then
         # Use libedit
         readline_link="-ledit"
@@ -2485,6 +2489,15 @@ else
           versions of libedit or readline])
     fi
 fi
+
+# if there is no readline, but we want to build with readline, we fail
+if [test "$want_to_use_readline" = "yes"] && [test ! -d "./cmd-line-utils/readline"]
+then
+    AC_MSG_ERROR([This commercially licensed MySQL source package can't
+          be built with libreadline. Please use --with-libedit to use
+          the bundled version of libedit instead.])
+fi
+
 fi
 
 AC_SUBST(readline_dir)