fix configure.ac.

configure.ac

@@ -6,11 +6,17 @@ AM_CONFIG_HEADER(config.h)
 AM_INIT_AUTOMAKE
 
 AC_PROG_CC
+AC_PROG_CXX
 AC_PROG_LIBTOOL
 AC_SUBST(LIBTOOL)dnl
 
 m4_include(config/ax_lib_mysql.m4)
 AX_LIB_MYSQL(,,AC_MSG_ERROR("Can't find mysql library" ))
+if test -n "$MYSQL_PLUGINDIR" && test "$libdir" == '${exec_prefix}/lib' ; then
+  AC_MSG_NOTICE(setting libdir to mysql plugin dir $MYSQL_PLUGINDIR)
+  libdir=$MYSQL_PLUGINDIR
+  AC_SUBST(libdir)
+fi
 
 m4_include(config/ax_mysql_bin.m4)
 AX_MYSQL_BIN
@@ -18,4 +24,4 @@ AX_MYSQL_BIN
 AC_C_CONST
 AC_TYPE_SIZE_T
 AC_CHECK_HEADERS(limits.h syslimits.h)
-AC_OUTPUT(Makefile)
\ No newline at end of file
+AC_OUTPUT(Makefile)