build/knem: Update to not use internal macros

Clean up the knem check, primarily to avoid the use of the
internal OPAL_CHECK_PACKAGE macro.  Since we're here, also
use AC_CACHE_CHECK around checks instead of the silent
check at the start of the macro.

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

Author: bwbarrett

config/opal_check_knem.m4

@@ -23,53 +23,45 @@ dnl
 # LDFLAGS, LIBS} as needed and runs action-if-found if there is
 # support, otherwise executes action-if-not-found
 AC_DEFUN([OPAL_CHECK_KNEM],[
-    if test -z "$opal_check_knem_happy" ; then
-        OPAL_VAR_SCOPE_PUSH([opal_check_knem_$1_save_CPPFLAGS opal_check_knem_dir])
-        AC_ARG_WITH([knem],
-                    [AS_HELP_STRING([--with-knem(=DIR)],
-                                    [Build knem Linux kernel module support, searching for headers in DIR/include])])
+    OPAL_VAR_SCOPE_PUSH([opal_check_knem_happy opal_check_knem_CPPFLAGS_save])
 
-        OPAL_CHECK_WITHDIR([knem], [$with_knem], [include/knem_io.h])
-        opal_check_knem_$1_save_CPPFLAGS="$CPPFLAGS"
+    AC_ARG_WITH([knem],
+                [AS_HELP_STRING([--with-knem(=DIR)],
+                                [Build knem Linux kernel module support, searching for headers in DIR/include])])
 
-        opal_check_knem_happy=no
+    opal_check_knem_CPPFLAGS_save="${CPPFLAGS}"
 
-        AS_IF([test "$with_knem" != "no"],
-              [AS_IF([test ! -z "$with_knem" && test "$with_knem" != "yes"],
-                     [opal_check_knem_dir="$with_knem"])
+    AS_IF([test -n "${with_knem}" -a "${with_knem}" != "yes" -a "${with_knem}" != "no"],
+          [$1_CPPFLAGS="-I${with_knem}/include"
+           CPPFLAGS="$CPPFLAGS ${$1_CPPFLAGS}"])
 
-               _OPAL_CHECK_PACKAGE_HEADER([ompi_check_knem],
-                                          [knem_io.h],
-                                          [$opal_check_knem_dir],
-                                          [opal_check_knem_happy="yes"],
-                                          [])],
-              [])
+    AC_CHECK_HEADER([knem_io.h], [opal_check_knem_happy="yes"], [opal_check_knem_happy="no"])
 
-        CPPFLAGS="$CPPFLAGS $ompi_check_knem_CPPFLAGS"
-
-        # need at least version 0x0000000b
-        if test "$opal_check_knem_happy" = "yes" ; then
-            AC_PREPROC_IFELSE([AC_LANG_PROGRAM([
+    # need at least version 0x0000000b
+    AS_IF([test "$opal_check_knem_happy" = "yes"],
+          [AC_CACHE_CHECK([for recent vesion of knem ABI],
+              [opal_check_knem_cv_abi_version],
+              [AC_PREPROC_IFELSE([AC_LANG_PROGRAM([[
 #include <knem_io.h>
-                                              ],[
+                                              ]], [[
 #if KNEM_ABI_VERSION < 0xc
 #error "Version less than 0xc"
 #endif
-                                              ])],
-                              [opal_check_knem_happy=yes],
-                              [opal_check_knem_happy=no])
-        fi
+                                              ]])],
+                              [opal_check_knem_cv_abi_version=yes],
+                              [opal_check_knem_cv_abi_version=no])])
+               AS_IF([test "${opal_check_knem_cv_abi_version}" = "no"],
+                     [opal_check_knem_happy=no])])
 
-        CPPFLAGS="$opal_check_knem_$1_save_CPPFLAGS"
+    CPPFLAGS="${opal_check_knem_CPPFLAGS_save}"
 
-        OPAL_SUMMARY_ADD([Transports], [Shared memory/Linux KNEM], [], [$opal_check_knem_happy])
-	OPAL_VAR_SCOPE_POP
-    fi
+    OPAL_SUMMARY_ADD([Transports], [Shared memory/Linux KNEM], [], [$opal_check_knem_happy])
 
     AS_IF([test "$opal_check_knem_happy" = "yes"],
-          [$1_CPPFLAGS="[$]$1_CPPFLAGS $ompi_check_knem_CPPFLAGS"
-           $2],
+          [$2],
           [AS_IF([test ! -z "$with_knem" && test "$with_knem" != "no"],
                  [AC_MSG_ERROR([KNEM support requested but not found.  Aborting])])
            $3])
+
+    OPAL_VAR_SCOPE_POP
 ])dnl