Override config-tool get_variable args for qmake

mesonbuild/dependencies/configtool.py

@@ -150,8 +150,11 @@ class ConfigToolDependency(ExternalDependency):
             return []
         return split_args(out)
 
+    def get_variable_args(self, variable_name: str) -> T.List[str]:
+        return [f'--{variable_name}']
+
     def get_configtool_variable(self, variable_name: str) -> str:
-        p, out, _ = Popen_safe(self.config + [f'--{variable_name}'])
+        p, out, _ = Popen_safe(self.config + self.get_variable_args(variable_name))
         if p.returncode != 0:
             if self.required:
                 raise DependencyException(

mesonbuild/dependencies/qt.py

@@ -350,6 +350,9 @@ class QmakeQtDependency(_QtBase, ConfigToolDependency, metaclass=abc.ABCMeta):
             return m.group(0).rstrip('.')
         return version
 
+    def get_variable_args(self, variable_name: str) -> T.List[str]:
+        return ['-query', f'{variable_name}']
+
     @abc.abstractmethod
     def get_private_includes(self, mod_inc_dir: str, module: str) -> T.List[str]:
         pass

test cases/frameworks/4 qt/meson.build

@@ -50,6 +50,9 @@ foreach qt : ['qt4', 'qt5', 'qt6']
     qtmodule = import(qt)
     assert(qtmodule.has_tools())
 
+    # Test that fetching a variable works and yields a non-empty value
+    assert(qtdep.get_variable('prefix', configtool: 'QT_INSTALL_PREFIX') != '')
+
     # The following has two resource files because having two in one target
     # requires you to do it properly or you get linker symbol clashes.