m4_define([b4_percent_define_if_define_],
[m4_define(m4_bpatsubst([b4_$1_if], [[-.]], [_]),
[b4_percent_define_flag_if(m4_default([$2], [$1]),
m4_define([b4_percent_define_if_define_],
[m4_define(m4_bpatsubst([b4_$1_if], [[-.]], [_]),
[b4_percent_define_flag_if(m4_default([$2], [$1]),