Detect LG_SIZEOF_PTR depending on MSVC platform target

configure.ac

@@ -166,6 +166,10 @@ if test "x${je_cv_msvc}" = "xyes" -a "x${ac_cv_header_inttypes_h}" = "xno"; then
   CPPFLAGS="$CPPFLAGS -I${srcdir}/include/msvc_compat/C99"
 fi
 
+if test "x${je_cv_msvc}" = "xyes" ; then
+  LG_SIZEOF_PTR=LG_SIZEOF_PTR_WIN
+  AC_MSG_RESULT([Using a predefined value for sizeof(void *): 4 for 32-bit, 8 for 64-bit])
+else
   AC_CHECK_SIZEOF([void *])
   if test "x${ac_cv_sizeof_void_p}" = "x8" ; then
     LG_SIZEOF_PTR=3
@@ -174,6 +178,7 @@ elif test "x${ac_cv_sizeof_void_p}" = "x4" ; then
   else
     AC_MSG_ERROR([Unsupported pointer size: ${ac_cv_sizeof_void_p}])
   fi
+fi
 AC_DEFINE_UNQUOTED([LG_SIZEOF_PTR], [$LG_SIZEOF_PTR])
 
 AC_CHECK_SIZEOF([int])

include/jemalloc/jemalloc_defs.h.in

@@ -33,5 +33,13 @@
  */
 #undef JEMALLOC_USE_CXX_THROW
 
+#ifdef _MSC_VER
+#  ifdef _WIN64
+#    define LG_SIZEOF_PTR_WIN 3
+#  else
+#    define LG_SIZEOF_PTR_WIN 2
+#  endif
+#endif
+
 /* sizeof(void *) == 2^LG_SIZEOF_PTR. */
 #undef LG_SIZEOF_PTR