Gaah; I meant to include a better comment in the last commit but had

forgotten to save before the commit was sent.

This comment explains why we're doing a cache check here rather than a
real check.

This commit was SVN r20975.

opal/mca/paffinity/posix/configure.m4

@@ -26,7 +26,9 @@ AC_DEFUN([MCA_paffinity_posix_CONFIG],[
     # Check to see if we have <unistd.h>
     AC_CHECK_HEADER([unistd.h], [paff_posix_happy=yes], [paff_posix_happy=no])
 
-    # Check to see if we have _SC_NPROCESSORS_ONLN
+    # Check to see if we have _SC_NPROCESSORS_ONLN (this was already
+    # checked up in the main configure.ac; just do a cache check
+    # here).
     AS_IF([test "$paff_posix_happy" = "yes"],
           [AC_MSG_CHECKING([for _SC_NPROCESSORS_ONLN])
            AS_IF([test "$ompi_cv_have__SC_NPROCESSORS_ONLN" = "yes"],