@ggouaillardet identified that HAVE_ALIAS_ATTRIBUTE was not properly
being defined in the embedded libfabric. This is because the
embedded configury missed the test for it (i.e., the real configure.ac
for libfabric always defines HAVE_ALIAS_ATTRIBUTE to 0 or 1 -- we
didn't emulate that properly here in libfabric's configure.m4).
Also, fix some grammar and properly escape another AC_MSG_CHECKING
message in libfabric's configure.m4.