qt: Fix build with gcc@9 (#11391)

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

@@ -86,6 +86,12 @@ class Qt(Package):
           working_dir='qtscript',
           when='@5.0:5.12 %gcc@8.3:')
 
+    # Fix build failure with newer versions of GCC
+    patch('https://github.com/qt/qtbase/commit/a52d7861edfb5956de38ba80015c4dd0b596259b.patch',
+          sha256='e10c871033568a9aed982628ed627356761f72f63c5fdaf11882dc147528e9ed',
+          working_dir='qtbase',
+          when='@5.10:5.12.0 %gcc@9:')
+
     depends_on("pkgconfig", type='build')
     # Use system openssl for security.
     depends_on("openssl@:1.0", when='@:5.9')