configure: clang supports -target rather than --target
In configure, we check whether the C compiler supports --target, and if it does we always pass that flag with the target triple to be less ambiguous, see the following excerpt:
# FP_CC_SUPPORTS_TARGET
# ---------------------
# Does CC support the --target=<triple> option? If so, we should pass it
# whenever possible to avoid ambiguity and potential compile-time errors (e.g.
# see #20162).
However, configure checks whether the compiler supports --target
specifically, while clang
supports -target
instead.
In a runtime retargetable future, the --target flag will be required to produce code for other architectures, so we ought to configure it correctly for clang too (i.e. -target
)