Warn about using the built-in MySQL library

configure.in

@@ -852,7 +852,8 @@ if true; then
     if test "$REDIRECT" = "0"; then
       if test "$DISCARD_PATH" = "0"; then
         echo "+--------------------------------------------------------------------+"
-        echo "| Warning:                                                           |"
+        echo "|                        *** WARNING ***                             |"
+        echo "|                                                                    |"
         echo "| You will be compiling the CGI version of PHP without any           |"
         echo "| redirection checking.  By putting this cgi binary somewhere in     |"
         echo "| your web space, users may be able to circumvent existing .htaccess |"
@@ -867,7 +868,8 @@ if true; then
     rm -f config.cache
 cat <<X
 +--------------------------------------------------------------------+
-| ATTENTION!                                                         |
+|                       *** ATTENTION ***                            |
+|                                                                    |
 | Something is likely to be messed up here, because the configure    |
 | script was not able to detect a simple feature on your platform.   |
 | This is often caused by incorrect configuration parameters. Please |
@@ -879,6 +881,20 @@ cat <<X
 X
   fi
 
+  if test "$MYSQL_MODULE_TYPE" = "builtin" ; then
+cat <<X
++--------------------------------------------------------------------+
+|                        *** WARNING ***                             |
+|                                                                    |
+| You chose to compile PHP with the built-in MySQL support.  If you  |
+| are compiling a server module, and intend to use other server      |
+| modules that also use MySQL (e.g, mod_auth_mysql, PHP 3.0,         |
+| mod_perl) you must NOT rely on PHP's built-in MySQL support, and   |
+| instead build it with your local MySQL support files, by adding    |
+| --with-mysql=/path/to/mysql to your configure line.                |
+X
+  fi
+
   echo "+--------------------------------------------------------------------+"
   echo "| License:                                                           |"
   echo "| This software is subject to the PHP License, available in this     |"

ext/mysql/config.m4

@@ -51,6 +51,7 @@ if test "$PHP_MYSQL" = "yes"; then
   PHP_SUBST(MYSQL_SUBDIRS)
   LIB_BUILD($ext_builddir/libmysql,$ext_shared,yes)
   AC_ADD_INCLUDE($ext_srcdir/libmysql)
+  MYSQL_MODULE_TYPE="builtin"
 elif test "$PHP_MYSQL" != "no"; then
   for i in $PHP_MYSQL; do
     if test -r $i/include/mysql/mysql.h; then
@@ -66,6 +67,7 @@ elif test "$PHP_MYSQL" != "no"; then
     AC_MSG_ERROR(Cannot find header files under $PHP_MYSQL)
   fi
 
+  MYSQL_MODULE_TYPE="external"
   for i in lib lib/mysql; do
     MYSQL_LIB_CHK($i)
   done
@@ -77,5 +79,7 @@ elif test "$PHP_MYSQL" != "no"; then
   AC_ADD_LIBRARY_WITH_PATH(mysqlclient, $MYSQL_LIB_DIR, MYSQL_SHARED_LIBADD)
 
   AC_ADD_INCLUDE($MYSQL_INC_DIR)
+else
+  MYSQL_MODULE_TYPE="none"
 fi
 PHP_SUBST(MYSQL_SHARED_LIBADD)