Improve Unicode support #1545

Job	Run time
code formatting check	19s
cppcheck	2m 14s
min features with gcc	3m 7s
min features with g++	2m 53s
min features with clang	2m 43s
max features with gcc	3m 26s
max features with g++	2m 34s
max features with clang	2m 42s
max features with gcc and DEBUG	3m 21s
max features with gcc for 32-bit arch (legacy OS)	2m 3s
max features with g++ for 32-bit arch (legacy OS)	1m 58s
max features with clang for 32-bit arch (legacy OS)	1m 58s
	29m 18s

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