Fix return value of project explorers macro expanders

They would claim that a variable that has an empty value is not a valid
variable and should not be replaced with that empty value.

Change-Id: I5ee9b950b611f8878efe2f86ac5b219d51194d48
Reviewed-by: Daniel Teske <daniel.teske@digia.com>

src/plugins/projectexplorer/buildconfiguration.cpp

@@ -72,8 +72,9 @@ bool BuildConfigMacroExpander::resolveMacro(const QString &name, QString *ret)
         *ret = m_bc->buildDirectory().toUserOutput();
         return true;
     }
-    *ret = Core::VariableManager::value(name.toUtf8());
-    return !ret->isEmpty();
+    bool found;
+    *ret = Core::VariableManager::value(name.toUtf8(), &found);
+    return found;
 }
 } // namespace Internal
 

src/plugins/projectexplorer/localapplicationrunconfiguration.cpp

@@ -55,8 +55,9 @@ bool FallBackMacroExpander::resolveMacro(const QString &name, QString *ret)
         *ret = m_target->project()->projectDirectory().toUserOutput();
         return true;
     }
-    *ret = Core::VariableManager::value(name.toUtf8());
-    return !ret->isEmpty();
+    bool found;
+    *ret = Core::VariableManager::value(name.toUtf8(), &found);
+    return found;
 }
 } // namespace Internal