Add the util/re2ptr.h helper file.
Add the util/re2ptr.h helper file.

This header file contains work-arounds for problems with using the RE2
library portably between different build environments.

parastoog/my-libaddressinput,roubert/libaddressinput,parastoog/my-libaddressinput,google/libaddressinput,dlyongemallo/libaddressinput,roubert/libaddressinput,mcanthony/libaddressinput,google/libaddressinput,google/libaddressinput,googlei18n/libaddressinput,parastoog/my-libaddressinput,dlyongemallo/libaddressinput,googlei18n/libaddressinput,mcanthony/libaddressinput,dlyongemallo/libaddressinput,mcanthony/libaddressinput,roubert/libaddressinput,googlei18n/libaddressinput