Fix manual dependency on jemalloc_test.h
Define _CRT_SPINCOUNT in test/src/mtx.c like in src/mutex.c
Define DLLEXPORT when building .jet objects
Replace variable arrays in tests with VARIABLE_ARRAY
Add missing $(EXE) to filter TESTS_UNIT_AUX_OBJS
Use C99 varadic macros instead of GCC ones
Rename "small" local variable, because windows headers #define it
Avoid pointer arithmetic on void* in test/integration/rallocx.c
Use ULL prefix instead of LLU for unsigned long longs

MSVC only supports the former.
Move __func__ to jemalloc_internal_macros.h

test/integration/aligned_alloc.c needs it.
Use a configure test to detect the form of malloc_usable_size in malloc.h
Move platform headers and tricks from jemalloc_internal.h.in to a new jemalloc_internal_decls.h header
Define INFINITY when it's not defined
Correctly return exit code from thd_join on Windows
Fixup after 3a730df (Avoid pointer arithmetic on void*[...])
STATIC_PAGE_SHIFT for cross-compiling jemalloc

Sets `STATIC_PAGE_SHIFT` for cross-compiling jemalloc to 12. A
shift of 12 represents a page size of 4k for practically all
platforms.
Make sure initialization occurs prior to running tests.
Use nallocx() rather than mallctl() to trigger initialization.

Use nallocx() rather than mallctl() to trigger initialization, because
nallocx() has no side effects other than initialization, whereas
mallctl() does a bunch of internal memory allocation.
Try to use __builtin_ffsl if ffsl is unavailable.

Some platforms (like those using Newlib) don't have ffs/ffsl. This commit adds a
check to configure.ac for __builtin_ffsl if ffsl isn't found. __builtin_ffsl
performs the same function as ffsl, and has the added benefit of being available
on any platform utilizing Gcc-compatible compiler.
Turn pages_purge in chunk_mmap.c into a no-op when madvise isn't present.

Platforms utilizing Newlib lack madvise. Sadly, barring platform-specific
haxors, there is nothing that can be done about this, so in those cases
pages_purge gets transformed into a no-op.