QbsProjectManager: Avoid allocations in string comparisons

Use case-insensitive comparisons instead of converting toLower() first.
Found by clazy.

Change-Id: I0d32b0ba7ccb5493d1c86d41044b09c8baed3dc8
Reviewed-by: Jake Petroules <jake.petroules@qt.io>
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/qbsprojectmanager/defaultpropertyprovider.cpp

@@ -341,12 +341,14 @@ QVariantMap DefaultPropertyProvider::autoGeneratedProperties(const ProjectExplor
             canonicalName.chop(version.size());
             if (!canonicalName.isEmpty() && !version.isEmpty()
                     && sysrootAbs.startsWith(developerPath)) {
-                if (sysrootAbs.toLower().endsWith(QStringLiteral("/%1.sdk")
-                                                  .arg(canonicalName + version)))
+                if (sysrootAbs.endsWith(QStringLiteral("/%1.sdk").arg(canonicalName + version),
+                                        Qt::CaseInsensitive)) {
                     data.insert(QLatin1String(XCODE_SDK), QString(canonicalName + version));
-                if (sysrootAbs.toLower().endsWith(QStringLiteral("/%1.sdk")
-                                                  .arg(canonicalName)))
+                }
+                if (sysrootAbs.endsWith(QStringLiteral("/%1.sdk").arg(canonicalName),
+                                        Qt::CaseInsensitive)) {
                     data.insert(QLatin1String(XCODE_SDK), canonicalName);
+                }
             }
         }
     }