CryptoPkg/Crt: turn strchr() into a function (CVE-2019-14553)
According to the ISO C standard, strchr() is a function. We #define it as
a macro. Unfortunately, our macro evaluates the first argument ("str")
twice. If the expression passed for "str" has side effects, the behavior
may be undefined.
In a later patch in this series, we're going to resurrect "inet_pton.c"
(originally from the StdLib package), which calls strchr() just like that: