A few error message fixes.

mesonbuild/interpreter.py

@@ -1704,6 +1704,8 @@ class Interpreter():
                      'for the dependency', mlog.bold(name))
             raise
         dep = self.subprojects[dirname].get_variable_method([varname], {})
+        if not isinstance(dep, (DependencyHolder, InternalDependencyHolder)):
+            raise InterpreterException('Fallback variable is not a dependency object.')
         # Check if the version of the declared dependency matches what we want
         if 'version' in kwargs:
             wanted = kwargs['version']

mesonbuild/modules/windows.py

@@ -38,6 +38,8 @@ class WindowsModule:
             rescomp = dependencies.ExternalProgram(rescomp_name, silent=True)
             res_args = extra_args + ['@INPUT@', '@OUTPUT@']
             suffix = 'o'
+        if not rescomp.found():
+            raise MesonException('Could not find Windows resource compiler %s.' % ' '.join(rescomp.get_command()))
         res_files = mesonlib.stringlistify(args)
         res_kwargs = {'output' : '@BASENAME@.' + suffix,
                       'arguments': res_args}