tests/ports/windows: temporarily disable some function cast warnings

make check in tests/ports/windows got new warnings from -Wcast-function-type
in gcc picky mode.

Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>

config/hwloc.m4

@@ -418,6 +418,7 @@ EOF])
 
 	    # -Wextra enables some -Wfoo that we want to disable it at some place
 	    _HWLOC_CHECK_GCC_OPTION([-Wmissing-field-initializers], [add], [AC_DEFINE(HWLOC_HAVE_GCC_W_MISSING_FIELD_INITIALIZERS, 1, [Define to 1 if gcc -Wmissing-field-initializers is supported and enabled])])
+	    _HWLOC_CHECK_GCC_OPTION([-Wcast-function-type], [add], [AC_DEFINE(HWLOC_HAVE_GCC_W_CAST_FUNCTION_TYPE, 1, [Define to 1 if gcc -Wcast-function-type is supported and enabled])])
 
             HWLOC_CFLAGS="$HWLOC_CFLAGS $add"
         fi

hwloc/topology-windows.c

@@ -1,6 +1,6 @@
 /*
  * Copyright © 2009 CNRS
- * Copyright © 2009-2019 Inria.  All rights reserved.
+ * Copyright © 2009-2020 Inria.  All rights reserved.
  * Copyright © 2009-2012, 2020 Université Bordeaux
  * Copyright © 2011 Cisco Systems, Inc.  All rights reserved.
  * See COPYING in top-level directory.
@@ -232,6 +232,10 @@ static void hwloc_win_get_function_ptrs(void)
 {
     HMODULE kernel32;
 
+#if HWLOC_HAVE_GCC_W_CAST_FUNCTION_TYPE
+#pragma GCC diagnostic ignored "-Wcast-function-type"
+#endif
+
     kernel32 = LoadLibrary("kernel32.dll");
     if (kernel32) {
       GetActiveProcessorGroupCountProc =
@@ -270,6 +274,10 @@ static void hwloc_win_get_function_ptrs(void)
       if (psapi)
         QueryWorkingSetExProc = (PFN_QUERYWORKINGSETEX) GetProcAddress(psapi, "QueryWorkingSetEx");
     }
+
+#if HWLOC_HAVE_GCC_W_CAST_FUNCTION_TYPE
+#pragma GCC diagnostic warning "-Wcast-function-type"
+#endif
 }
 
 /*