util: move mallinfo compat glue from selinux code into generic code

src/basic/mallinfo-util.h

@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <malloc.h>
+
+#if HAVE_MALLINFO2
+#  define HAVE_GENERIC_MALLINFO 1
+typedef struct mallinfo2 generic_mallinfo;
+static inline generic_mallinfo generic_mallinfo_get(void) {
+        return mallinfo2();
+}
+#elif HAVE_MALLINFO
+#  define HAVE_GENERIC_MALLINFO 1
+typedef struct mallinfo generic_mallinfo;
+static inline generic_mallinfo generic_mallinfo_get(void) {
+        /* glibc has deprecated mallinfo(), let's suppress the deprecation warning if mallinfo2() doesn't
+         * exist yet. */
+DISABLE_WARNING_DEPRECATED_DECLARATIONS
+        return mallinfo();
+REENABLE_WARNING
+}
+#else
+#  define HAVE_GENERIC_MALLINFO 0
+#endif