Fix compilation problems with modern versions of Folly

[SashaNullptr]

Attempting to compile WDT against modern versions of Folly results in the following error when linking wdtbin (aliased to wdt).

libfolly4wdt.so: undefined reference to `folly::strlcpy(char*, char const*, unsigned long)'

It seems that the source files that define folly::strlcpy, namely lang/CString.cpp need to be included explicitly.

It also appears that this problem has already been addressed by a fork of WDT.

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[SashaNullptr]

Heh, just noticed the maintainer that I linked to already submitted a PR for this problem at #201

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[davide125]

Duplicate of #201