[krbdev.mit.edu #8928] [PATCH] Constructor/destructor configure check fails on certain compilers

<URL: https://krbdev.mit.edu/rt/Ticket/Display.html?id=8928 >

> conftest.c:25:15: error: implicit declaration of function 'unlink' is
invalid in C99 [-Werror,-Wimplicit-function-declaration]

Was this configure run done with CPPFLAGS=-Werror or similar?

If not, what version of clang was this?

(There seem to be other, more immediate problems with configuring with -Werror
in the compiler flags, such as TRY_WARN_CC_FLAG_1 failing in AC_TRY_COMPILE([],
1;, ...) because "1;" generates an unused value warning. So probably something
else is going on.)