* tests/calc.at, tests/output.at, tests/regression.at,

* tests/testsuite.at, tests/torture.at: Rely on Autotest 2.52g:
now the tests are run in private dirs, therefore AC_CLEANUP and
family can be simplified to 0-ary.
* tests/atlocal.in: Now that we run `elsewhere' than in tests/,
use abs. path to find config.h.

tests/calc.at

@@ -338,8 +338,14 @@ AT_CHECK([bison calc.y -o calc.c m4_bpatsubst([$1], [--yyerror-verbose])],
 # Maybe some day we will have proper Autoconf macros to disable these
 # warnings, but this place is not the right one for that.
 # So let's keep only GCC warnings, which we know are sane.
-AT_CHECK([$CC $CFLAGS $CPPFLAGS calc.c -o calc], 0, [], [stderr])
-AT_CHECK([if test "$GCC" = yes; then cat stderr; else true; fi])
+# Well, that's only part of the story: some assemblers issue warnings
+# which can be totally useless, and actually polluting.  It seems that
+# the best bet be to completely ignore stderr, but to pass -Werror
+# to GCC.
+if test "$GCC" = yes; then
+  CFLAGS="$CFLAGS -Werror"
+fi
+AT_CHECK([$CC $CFLAGS $CPPFLAGS calc.c -o calc], 0, [], [ignore])
 
 # Test the priorities.
 _AT_CHECK_CALC([$1],
@@ -377,7 +383,7 @@ _AT_CHECK_CALC_ERROR([$1],
                      [2.0:2.1],
                      [unexpected `'+''])
 
-AT_CLEANUP(calc calc.c calc.h calc.output)
+AT_CLEANUP
 ])# AT_CHECK_CALC