Improve Unicode support #1502

Job	Run time
code formatting check	36s
cppcheck	3m 26s
min features with gcc	3m 16s
min features with g++	3m 23s
min features with clang	3m 6s
max features with gcc	4m 7s
max features with g++	2m 46s
max features with clang	5m 3s
max features with gcc and DEBUG	2m 32s
max features with gcc for 32-bit arch (legacy OS)	3m 5s
max features with g++ for 32-bit arch (legacy OS)	1m 57s
max features with clang for 32-bit arch (legacy OS)	2m 4s
	35m 21s

Provide feedback