- make sure to include sql/share/errmsg.txt into the source distribution

sql/share/Makefile.am:
  - make sure to include errmsg.txt into the source distribution

sql/share/Makefile.am

 ## Process this file with automake to create Makefile.in
 
+extra_DIST= errmsg.txt
+
 dist-hook:
 	for dir in charsets @AVAILABLE_LANGUAGES@; do \
 	  test -d $(distdir)/$$dir || mkdir $(distdir)/$$dir; \