have_const(const, headers = nil, opt = "", &b)
Instance Public methods
Returns whether or not the constant const is defined. You may
optionally pass the type of const as
[const, type], such as:
have_const(%w[PTHREAD_MUTEX_INITIALIZER pthread_mutex_t], "pthread.h")
You may also pass additional headers to check against in
addition to the common header files, and additional flags to
opt which are then passed along to the compiler.
If found, a macro is passed as a preprocessor co