WL#3462 Add testing of MySQL client ABI to prevent unintentional ABI breaks

BUG#23427 incompatible ABI change in 5.0.26?
   - Use the icheck tool if avaliable and compare the current mysql.h to a version
controlled reference file 


BitKeeper/etc/ignore:
  Added include/check_abi include/mysql_h.ic to the ignore list
configure.in:
  Look for icheck in configure
include/Makefile.am:
  Add rule to build mysql_h.ic if icheck is avaliable
  Add rule to compare mysql_h.ic to the version
  controlled reference file mysql_h_abi.ic
include/mysql.h:
  Add comment about taking care when editing mysql.h
  Add example how to add reserved fiels in the structs to
  allow for features to be added without breaking ABI
include/mysql_h_abi.ic:
  Add new file describing the libmysqlclient ABI used as a reference to detect ABI breakage

1 files changed, 11 insertions, 0 deletions

diff --git a/include/mysql.h b/include/mysql.h
index 143f6752c46..bc99b6f6ba1 100644
--- a/include/mysql.h
+++ b/include/mysql.h
@@ -14,6 +14,17 @@
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
 
+/*
+  This file defines the client API to MySQL and also the ABI of the
+  dynamically linked libmysqlclient.
+
+  The ABI should never be changed in a released product of MySQL
+  thus you need to take great care when changing the file. In case
+  the file is changed so the ABI is broken, you must also
+  update the SHAREDLIB_MAJOR_VERSION in configure.in .
+
+*/
+
 #ifndef _mysql_h
 #define _mysql_h