PATCH: supply useful default for RUNTEST in DejaGnu testsuite

This patch is a step towards being able to remove RUNTESTDEFAULTFLAGS 
entirely from Makefile.am.  It provides a useful default for RUNTEST:  
the "runtest" program in the directory containing the testsuite's 
"testsuite" directory, which is the DejaGnu source directory in practice.

Some minor cleanups are also included:  grepping the entire testsuite 
for "RUNTESTFLAGS" yields no hits except for this file, so the unused 
variable is removed; also, the global variables referenced but not used 
in runtest_start are removed.

Does runtest_start actually do anything useful, or should it be removed 
as well?  The DejaGnu "runtest" program is batch-oriented, so the manual 
seems to suggest that runtest_start should be removed entirely; I think 
that its sanity check that $RUNTEST can be found should be promoted to 
top-level and failure converted to a fatal error.

----
ChangeLog entry:
	* testsuite/lib/runtest.exp: Use "testsuite file" to locate
	default runtest executable instead of implicitly searching PATH.
	Remove unused RUNTESTFLAGS Tcl variable.
	(runtest_start): Remove unused global variable links.
----
patch:
----
diff --git a/testsuite/lib/runtest.exp b/testsuite/lib/runtest.exp
index fa48175..399e174 100644
--- a/testsuite/lib/runtest.exp
+++ b/testsuite/lib/runtest.exp
@@ -20,7 +20,7 @@
 
 global RUNTEST
 if {![info exists RUNTEST]} then {
-    set RUNTEST [transform runtest]
+    set RUNTEST [file join [file dirname [testsuite file -source -top]] runtest]
 }
 
 if {![info exists EXPECT]} {
@@ -28,11 +28,6 @@ if {![info exists EXPECT]} {
     verbose "EXPECT defaulting to $EXPECT" 2
 }
 
-global RUNTESTFLAGS
-if {![info exists RUNTESTFLAGS]} then {
-    set RUNTESTFLAGS "-v -v -a"
-}
-
 #
 # runtest_version -- extract and print the version number
 #
@@ -61,13 +56,7 @@ proc runtest_exit { } {
 # runtest_start -- start everything
 #
 proc runtest_start { } {
-    global verbose
-    global spawn_id
-    global subdir
-    global srcdir
-    global objdir
     global RUNTEST
-    global RUNTESTFLAGS
 
     if {[which $RUNTEST] != 0} then {
 	perror "Can't find $RUNTEST"
----


-- Jacob