sim: testsuite: unify basic C compiler checks

Both bfin & cris ports test the C compiler to see if it works, but in
their own way.  Unify the checks in the common code so we can leverage
them in more ports in the future, and collapse the bfin & cris code.

sim/testsuite/cris/c/c.exp

@@ -33,11 +33,8 @@ if [istarget cris*-*-elf] {
 }
 
 # Using target_compile, since it is less noisy,
-global objdir
-if { [target_compile $srcdir/$subdir/hello.c $objdir/compilercheck.x \
-	  "executable" "" ] == "" } {
-    set has_cc 1
-
+global global_cc_works
+if { $global_cc_works == 1 } {
     # Now check if we can link a program dynamically, and where
     # libc.so is located.  If it is, we provide a sym link to the
     # directory (which must end in /lib) in [pwd], so /lib/ld.so.1 is
@@ -45,8 +42,9 @@ if { [target_compile $srcdir/$subdir/hello.c $objdir/compilercheck.x \
     # replacing the board ldflags like below as we don't care about
     # detrimental effects on the executable from the specs and
     # -static in the board ldflags, we just add -Bdynamic.
+    global objdir
     if [regexp "(.*/lib)/libc.so" \
-	    [target_compile $srcdir/$subdir/hello.c $objdir/compilercheck.x \
+	    [target_compile $srcdir/lib/compilercheck.c $objdir/compilercheck.x \
 		 "executable" \
 		 "ldflags=-print-file-name=libc.so -Wl,-Bdynamic"] \
 	    xxx libcsodir]  {
@@ -54,9 +52,7 @@ if { [target_compile $srcdir/$subdir/hello.c $objdir/compilercheck.x \
 	verbose -log "Creating link to $libcsodir in [pwd]"
 	file link lib $libcsodir
     }
-} {
-    verbose -log "Can't execute C compiler"
-    set has_cc 0
+    file delete $objdir/compilercheck.x
 }
 
 # Like istarget, except take a list of targets as a string.
@@ -92,7 +88,7 @@ foreach src [lsort [glob -nocomplain $srcdir/$subdir/*.c]] {
     }
 
     # Note absence of CC in results, but don't make a big fuss over it.
-    if { $has_cc == 0 } {
+    if { $global_cc_works == 0 } {
 	untested $testname
 	continue
     }