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.