build: don't use unicode characters in configure.ac
build: don't use unicode characters in configure.ac

Replace unicode apostrophes with their ASCII counterparts.

Signed-off-by: Bartosz Golaszewski <108de5fbc428215dc26df4468b48691526611148@gmail.com>

brgl/libgpiod,brgl/libgpiod,brgl/libgpiod,brgl/libgpiod