bison generated code produces warning in -Wall mode of gcc

Binary package hint: bison

I previously used bison 1.875 and upgraded - because of code generation issues with gcc-4.3 - to bison 2.3.

Now the generated code produces a warning in yyget_column/yyset_column :

.../AC.c:10477: warning: no previous prototype for 'ACget_column'
.../AC.c:10557: warning: no previous prototype for 'ACset_column'

where AC is my prefix. I think this is because the functions are not declared static nor extern and gcc likes this to be so.

ProblemType: Bug
Architecture: i386
Dependencies:
 libgcc1 1:4.3.3-5ubuntu4
 m4 1.4.11-1
 gcc-4.3-base 4.3.3-5ubuntu4
 findutils 4.4.0-2ubuntu4
 libc6 2.9-4ubuntu6
DistroRelease: Ubuntu 9.04
Package: bison 1:2.3.dfsg-5
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, user)
 LANG=en_US.iso-8859-15
 SHELL=/bin/bash
SourcePackage: bison
Uname: Linux 2.6.28-14-generic i686