don't force dependecy on shasum when it is not needed

shasum is only needed to detect a bug in some version of gnumkae
do not burden platform with a non-impacted gnu make with
that requirement

configure.in

@@ -3613,14 +3613,6 @@ dnl ===================================================================
 AC_MSG_CHECKING([whether to enable pch feature])
 AC_MSG_RESULT([no, obsolete])
 
-dnl ===================================================================
-dnl Search all the common names for sha1sum
-dnl ===================================================================
-AC_PATH_PROGS(SHA1SUM, sha1sum sha1 shasum)
-if test -z "$SHA1SUM"; then
-    AC_MSG_ERROR([install the approproate SHA-1 checksumming program for this OS])
-fi
-
 dnl ===================================================================
 dnl Search all the common names for GNU make
 dnl ===================================================================
@@ -3653,6 +3645,14 @@ if test "$_make_longver" -ge "038200"; then
 
 elif test "$_make_longver" -ge "038100"; then
     AC_MSG_RESULT([$GNUMAKE $_make_version])
+
+    dnl ===================================================================
+    dnl Search all the common names for sha1sum
+    dnl ===================================================================
+    AC_PATH_PROGS(SHA1SUM, sha1sum sha1 shasum)
+    if test -z "$SHA1SUM"; then
+        AC_MSG_ERROR([install the approproate SHA-1 checksumming program for this OS])
+    fi
     AC_MSG_CHECKING([for GNU make bug 20033])
     TESTGMAKEBUG20033=`mktemp -d tmp.XXXXXX`
     cat > $TESTGMAKEBUG20033/Makefile << EOF