bug#50271: In the src/dfasearch.c file I find the function dfasupported undefined

[yangzhuangzhuang]

The function dfasupported is referenced in the submission below, but is not 
found with the 
definition.commit:https://git.savannah.gnu.org/cgit/grep.git/commit/src?id=ae65513edc80a1b65f19264b9bed95d870602967