Refactor to support more varied testing.

Refactor the test harness to support three types of tests:
- unit: White box unit tests.  These tests have full access to all
  internal jemalloc library symbols.  Though in actuality all symbols
  are prefixed by jet_, macro-based name mangling abstracts this away
  from test code.
- integration: Black box integration tests.  These tests link with
  the installable shared jemalloc library, and with the exception of
  some utility code and configure-generated macro definitions, they have
  no access to jemalloc internals.
- stress: Black box stress tests.  These tests link with the installable
  shared jemalloc library, as well as with an internal allocator with
  symbols prefixed by jet_ (same as for unit tests) that can be used to
  allocate data structures that are internal to the test code.

Move existing tests into test/{unit,integration}/ as appropriate.

Split out internal parts of jemalloc_defs.h.in and put them in
jemalloc_internal_defs.h.in.  This reduces internals exposure to
applications that #include <jemalloc/jemalloc.h>.

Refactor jemalloc.h header generation so that a single header file
results, and the prototypes can be used to generate jet_ prototypes for
tests.  Split jemalloc.h.in into multiple parts (jemalloc_defs.h.in,
jemalloc_macros.h.in, jemalloc_protos.h.in, jemalloc_mangle.h.in) and
use a shell script to generate a unified jemalloc.h at configure time.

Change the default private namespace prefix from "" to "je_".

Add missing private namespace mangling.

Remove hard-coded private_namespace.h.  Instead generate it and
private_unnamespace.h from private_symbols.txt.  Use similar logic for
public symbols, which aids in name mangling for jet_ symbols.

Add test_warn() and test_fail().  Replace existing exit(1) calls with
test_fail() calls.

test/integration/jemalloc_integration.h.in

@@ -0,0 +1,50 @@
+/*
+ * This header should be included by tests, rather than directly including
+ * jemalloc/jemalloc.h, because --with-install-suffix may cause the header to
+ * have a different name.
+ */
+#include "jemalloc/jemalloc@install_suffix@.h"
+#include "jemalloc/internal/jemalloc_internal.h"
+
+/* Abstraction layer for threading in tests. */
+#ifdef _WIN32
+#include <windows.h>
+
+typedef HANDLE je_thread_t;
+
+void
+je_thread_create(je_thread_t *thread, void *(*proc)(void *), void *arg)
+{
+	LPTHREAD_START_ROUTINE routine = (LPTHREAD_START_ROUTINE)proc;
+	*thread = CreateThread(NULL, 0, routine, arg, 0, NULL);
+	if (*thread == NULL)
+		test_fail("Error in CreateThread()\n");
+}
+
+void
+je_thread_join(je_thread_t thread, void **ret)
+{
+
+	WaitForSingleObject(thread, INFINITE);
+}
+
+#else
+#include <pthread.h>
+
+typedef pthread_t je_thread_t;
+
+void
+je_thread_create(je_thread_t *thread, void *(*proc)(void *), void *arg)
+{
+
+	if (pthread_create(thread, NULL, proc, arg) != 0)
+		test_fail("Error in pthread_create()\n");
+}
+
+void
+je_thread_join(je_thread_t thread, void **ret)
+{
+
+	pthread_join(thread, ret);
+}
+#endif