byte-compile-maybe-guarded is a Lisp macro in `bytecomp.el'.

(byte-compile-maybe-guarded CONDITION &rest BODY)

Execute forms in BODY, potentially guarded by CONDITION.
CONDITION is a variable whose value is a test in an `if' or `cond'.
BODY is the code to compile in the first arm of the if or the body of
the cond clause. If CONDITION's value is of the form (fboundp 'foo)
or (boundp 'foo), the relevant warnings from BODY about foo's
being undefined (or obsolete) will be suppressed.

If CONDITION's value is (not (featurep 'emacs)) or (featurep 'xemacs),
that suppresses all warnings during execution of BODY.