Do not mark malloc_conf as weak on Windows.
Do not mark malloc_conf as weak on Windows.

This works around malloc_conf not being properly initialized by at least
the cygwin toolchain.  Prior build system changes to use
-Wl,--[no-]whole-archive may be necessary for malloc_conf resolution to
work properly as a non-weak symbol (not tested).

jemalloc/jemalloc-cmake,wqfish/jemalloc,jemalloc/jemalloc-cmake,wqfish/jemalloc,jemalloc/jemalloc-cmake,wqfish/jemalloc,jemalloc/jemalloc-cmake,wqfish/jemalloc,wqfish/jemalloc