Different conflicts between byacc and bison

Hello !

I'm trying to build the CFRONT parser with bison instead of byacc and 
I've got bison to accept the grammar 
https://github.com/mingodad/cfront-3/blob/master/src/gram.y but the 
generated parser by bison has a small difference in the conflicts found 
in the grammar (see bellow) and also by comparison I tested the last C++ 
grammar from GCC 3.3.6 
https://github.com/gcc-mirror/gcc/blob/releases/gcc-3.3.6/gcc/cp/parse.y 
and there byacc and bison seem to agree on the conflicts.

I tested with two bison versions and both give the same results but the 
generated parser do not pass the tests.

I'm pointing this here because it seems to be a good example of a corner 
case maybe not noticed so far.


bison (GNU Bison) 3.0.4
bison (GNU Bison) 3.8.2

byacc - 1.9 20140715

====

cfront-3/src$ bison -y gram.y
gram.y: warning: 20 shift/reduce conflicts [-Wconflicts-sr]
gram.y: warning: 4 reduce/reduce conflicts [-Wconflicts-rr]

cfront-3/srv$ byacc gram.y
byacc: 21 shift/reduce conflicts, 3 reduce/reduce conflicts.

====

====

gcc-3.3.6/gcc/cp$ bison -y parse.y
parse.y: warning: 33 shift/reduce conflicts [-Wconflicts-sr]
parse.y: warning: 58 reduce/reduce conflicts [-Wconflicts-rr]

gcc-3.3.6/gcc/cp$ byacc parse.y
byacc: 33 shift/reduce conflicts, 58 reduce/reduce conflicts.

====

Cheers !