Fix 'make test' failing without any really wrong tests.

The reason was that the invocation of the cpuid_tool through the makefile
was using LD_LIBRARY_PATH=. to force link&use of the latest-build libcpuid
library. This doesn't seem to work, so using LD_PRELOAD to explicitly load
libcpuid.so into cpuid_tool.

The committed approach of course doesn't work on Mac OS X, where
make test-old should be used.

Makefile.am

@@ -15,7 +15,7 @@ consistency:
 test: test-fast
 
 test-fast:
-	LD_LIBRARY_PATH=$(top_builddir)/libcpuid/.libs $(top_srcdir)/tests/run_tests.py $(top_builddir)/cpuid_tool/.libs/cpuid_tool $(top_srcdir)/tests 
+	LD_PRELOAD=$(top_builddir)/libcpuid/.libs/libcpuid.so $(top_srcdir)/tests/run_tests.py $(top_builddir)/cpuid_tool/.libs/cpuid_tool --show-test-fast-warning $(top_srcdir)/tests
 
 test-old:
 	$(top_srcdir)/tests/run_tests.py $(top_builddir)/cpuid_tool/cpuid_tool $(top_srcdir)/tests

tests/run_tests.py

@@ -12,6 +12,7 @@ fields = [ "family", "model", "stepping", "extfamily", "extmodel", "cores",
 
 args = sys.argv
 fix = False
+show_test_fast_warning = False
 
 if len(args) < 3:
 	print """
@@ -31,6 +32,9 @@ for arg in args[2:]:
 	if arg == "--fix":
 		fix = True
 		continue
+	if arg == "--show-test-fast-warning":
+		show_test_fast_warning = True
+		continue
 	if os.path.isdir(arg):
 		# gather all *.test files from subdirs amd and intel:
 		for dirpath, dirnames, filenames in os.walk(arg):
@@ -120,5 +124,10 @@ for test_file_name in filelist:
 			errors = True
 		build_output = False
 
-if not errors:
+if errors:
+	if show_test_fast_warning:
+		print """
+You're running tests in fast mode; before taking any action on the errors
+above, please confirm that the slow mode ('make test-old') also fails."""
+else:
 	print "All successfull!"