add basic concurrency/IO test: tests that stdin is non-blocking

testsuite/tests/ghc-regress/lib/IO/Makefile

 TOP=../../../..
 include $(TOP)/mk/boilerplate.mk
 include $(TOP)/mk/test.mk
+
+test.concio001:
+	@$(TEST_HC) --make -fforce-recomp -v0 concio001 -o concio001 
+	@(sleep 0.2; echo x) | ./concio001
+
+test.concio001.thr:
+	@$(TEST_HC) --make -fforce-recomp -v0 -threaded concio001 -o concio001 
+	@(sleep 0.2; echo x) | ./concio001

testsuite/tests/ghc-regress/lib/IO/all.T

@@ -88,3 +88,5 @@ clean(['tmp'])
 test('countReaders001', expect_broken(629), compile_and_run, [''])
 clean(['countReaders001.txt'])
 
+test('concio001', normal, run_command, ['$MAKE -s --no-print-directory test.concio001'])
+test('concio001.thr', normal, run_command, ['$MAKE -s --no-print-directory test.concio001.thr'])

testsuite/tests/ghc-regress/lib/IO/concio001.stdout

+child
+parent

testsuite/tests/ghc-regress/lib/IO/concio001.thr.stdout

+child
+parent