mempool: enable with MSVC

The issues that were preventing mempool from getting compiled with
MSVC were fixed, so now it should not be excluded from the
build anymore.

Signed-off-by: Andre Muezerie <andremue@linux.microsoft.com>
Reviewed-by: Morten Brørup <mb@smartsharesystems.com>
Acked-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>

lib/mempool/meson.build

@@ -1,12 +1,6 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright(c) 2017 Intel Corporation
 
-if is_ms_compiler
-    build = false
-    reason = 'not supported building with Visual Studio Toolset'
-    subdir_done()
-endif
-
 extra_flags = []
 
 foreach flag: extra_flags