add OpenH264 #2234

Job	Run time
code formatting check	14s
cppcheck	3m 48s
min features with gcc	2m 59s
min features with g++	1m 48s
min features with clang	2m 43s
max features with gcc	3m 32s
max features with g++	2m 32s
max features with clang	3m 39s
max features with clang and AddressSanitized	3m 1s
max features with gcc and DEBUG	2m 13s
max features with gcc for 32-bit arch (legacy OS)	2m 0s
max features with g++ for 32-bit arch (legacy OS)	1m 34s
max features with clang for 32-bit arch (legacy OS)	1m 44s
	31m 47s

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