wget: fixing compilation issue with gcc11+ on rhel7 (#30858)

var/spack/repos/builtin/packages/wget/package.py

@@ -53,6 +53,16 @@ class Wget(AutotoolsPackage, GNUMirrorPackage):
 
     build_directory = 'spack-build'
 
+    def flag_handler(self, name, flags):
+        # gcc11 defaults to c17, which breaks compilation with older
+        # glibc versions as shipped with rhel7 and likely other OS
+        # versions too, feel free to add as necessary
+        older_glibc = self.spec.satisfies('os=rhel7') or \
+            self.spec.satisfies('os=centos7')
+        if self.spec.satisfies('%gcc@11:') and older_glibc and name.lower() == 'cflags':
+            flags.append(self.compiler.c11_flag)
+        return (None, None, flags)
+
     def configure_args(self):
         spec = self.spec