Improve Unicode support #1560

Job	Run time
cppcheck	2m 12s
code formatting check	39s
min features with gcc	2m 40s
min features with g++	3m 0s
min features with clang	3m 53s
max features with gcc	4m 31s
max features with g++	2m 40s
max features with clang	4m 29s
max features with gcc and DEBUG	2m 48s
max features with gcc for 32-bit arch (legacy OS)	2m 12s
max features with g++ for 32-bit arch (legacy OS)	2m 3s
max features with clang for 32-bit arch (legacy OS)	2m 35s
	33m 42s

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