References: bsc#1257399 - Package xen doesn't build with glibc 2.43

Ignore instances of,
error: assignment discards "const" qualifier from pointer target type [-Werror=discarded-qualifiers]
There are three instances in libxl_cpuid.c and one in libxl_internal.c

Index: xen-4.21.0-testing/tools/libs/light/libxl_cpuid.c
===================================================================
--- xen-4.21.0-testing.orig/tools/libs/light/libxl_cpuid.c
+++ xen-4.21.0-testing/tools/libs/light/libxl_cpuid.c
@@ -407,6 +407,8 @@ int libxl_cpuid_parse_config(libxl_cpuid
     return 2;
 }
 
+#pragma GCC diagnostic ignored "-Wdiscarded-qualifiers"
+
 /* parse a single list item from the legacy Python xend syntax, where
  * the strings for each register were directly exposed to the user.
  * Used for maintaining compatibility with older config files
Index: xen-4.21.0-testing/tools/libs/light/libxl_internal.c
===================================================================
--- xen-4.21.0-testing.orig/tools/libs/light/libxl_internal.c
+++ xen-4.21.0-testing/tools/libs/light/libxl_internal.c
@@ -293,6 +293,8 @@ char *libxl__strndup(libxl__gc *gc, cons
     return s;
 }
 
+#pragma GCC diagnostic ignored "-Wdiscarded-qualifiers"
+
 char *libxl__dirname(libxl__gc *gc, const char *s)
 {
     char *c = strrchr(s, '/');