backport fix from upstream

http://bugs.gentoo.org/151935#c6

--- configure
+++ configure
@@ -23872,7 +23872,7 @@
   mysql_libs=`$MYSQL_CONFIG --libs|sed -e "s/'//g"`
   LIBRDF_LIBS="$LIBRDF_LIBS $mysql_libs"
       # Stop the MySQL config program adding -O<n> options to CFLAGS
-  mysql_cflags=`$MYSQL_CONFIG --cflags | sed -e "s/'//g" -e "s/-O[1-9]*//" `
+  mysql_cflags=`$MYSQL_CONFIG --cflags | sed -e "s/'//g" -e "s/-O[A-Za-z0-9]*//" `
   LIBRDF_CPPFLAGS="$LIBRDF_CPPFLAGS $mysql_cflags"
   fi
 if test $sqlite_storage  = yes; then
@@ -24259,12 +24259,12 @@
 fi
 
 if test "$USE_MAINTAINER_MODE" = yes -a $release_version = no; then
-      CFLAGS=`echo $CFLAGS | sed s/-O[1-9]*//`
-  CXXFLAGS=`echo $CXXFLAGS | sed s/-O[1-9]*//`
-  STANDARD_CFLAGS=`echo $STANDARD_CFLAGS | sed s/-O[1-9]*//`
-  LIBRDF_CPPFLAGS=`echo $LIBRDF_CPPFLAGS | sed s/-O[1-9]*//`
-  LIBRDF_EXTERNAL_CPPFLAGS=`echo $LIBRDF_EXTERNAL_CPPFLAGS | sed s/-O[1-9]*//`
-  LIBRDF_INTERNAL_CPPFLAGS=`echo $LIBRDF_INTERNAL_CPPFLAGS | sed s/-O[1-9]*//`
+      CFLAGS=`echo $CFLAGS | sed s/-O[A-Za-z0-9]*//`
+  CXXFLAGS=`echo $CXXFLAGS | sed s/-O[A-Za-z0-9]*//`
+  STANDARD_CFLAGS=`echo $STANDARD_CFLAGS | sed s/-O[A-Za-z0-9]*//`
+  LIBRDF_CPPFLAGS=`echo $LIBRDF_CPPFLAGS | sed s/-O[A-Za-z0-9]*//`
+  LIBRDF_EXTERNAL_CPPFLAGS=`echo $LIBRDF_EXTERNAL_CPPFLAGS | sed s/-O[A-Za-z0-9]*//`
+  LIBRDF_INTERNAL_CPPFLAGS=`echo $LIBRDF_INTERNAL_CPPFLAGS | sed s/-O[A-Za-z0-9]*//`
   fi