build: Fix sed expression used to ignore subconfig args

The ignore argument to PAC_CONFIG_SUBDIR_ARGS is an m4 list of
sed expressions.  --with-platform=.* ignored not just the platform
argument, but everything after it.  Fix the regular expressions to
ignore everything until the next whitespace.  This probably still
isn't entirely right, because it will fail if the argument has
spaces in it (like a path with spaces), but we fail that test
so many other places that it does not add to the fail.

Signed-off-by: Brian Barrett <bbarrett@amazon.com>

config/ompi_setup_prrte.m4

@@ -148,7 +148,7 @@ dnl        [internal_prrte_args="$internal_prrte_args --with-platform=$with_prrt
             [[--with-libevent=internal], [--with-hwloc=internal],
              [--with-libevent=external], [--with-hwloc=external],
              [--with-pmix=internal], [--with-pmix=external],
-             [--with-platform=.*]],
+             [--with-platform=[[^ 	]]*]],
             [], [internal_prrte_happy="no"])
     OPAL_3RDPARTY_DIST_SUBDIRS="$OPAL_3RDPARTY_DIST_SUBDIRS prrte"
 

config/opal_config_pmix.m4

@@ -91,7 +91,7 @@ AC_DEFUN([OPAL_CONFIG_PMIX], [
          PAC_CONFIG_SUBDIR_ARGS([3rd-party/openpmix], [$internal_pmix_args],
                            [[--with-libevent=internal], [--with-hwloc=internal],
                             [--with-libevent=external], [--with-hwloc=external],
-                            [--with-pmix=.*], [--with-platform=.*]],
+                            [--with-pmix=[[^ 	]]*], [--with-platform=[[^ 	]]*]],
                            [internal_pmix_happy=1])
          OPAL_3RDPARTY_DIST_SUBDIRS="$OPAL_3RDPARTY_DIST_SUBDIRS openpmix"])