ea935df632
WRAPPER_EXTRA_LDFLAGS is both no longer used, and even if we fixed to
use the new names (i.e., <PACKAGE>_WRAPPER_EXTRA_LDFLAGS), it contains
a token that will not be understandable in Makefile.ams: @{libdir}.
Hence, update all instances to use <PACKAGE>_PKG_CONFIG_LDFLAGS, which
does not contain the @{libdir} token. See comment in
opal_setup_wrappers.m4 for an explanation.