diff --git a/plugins/custom-definesandincludes/compilerprovider/settingsmanager.cpp b/plugins/custom-definesandincludes/compilerprovider/settingsmanager.cpp
--- a/plugins/custom-definesandincludes/compilerprovider/settingsmanager.cpp
+++ b/plugins/custom-definesandincludes/compilerprovider/settingsmanager.cpp
@@ -81,10 +81,10 @@
 ParserArguments defaultArguments()
 {
     const static ParserArguments arguments{
-        QStringLiteral("-ferror-limit=100 -fspell-checking -Wdocumentation -Wunused-parameter -Wunreachable-code -Wall -std=c99"),
-        QStringLiteral("-ferror-limit=100 -fspell-checking -Wdocumentation -Wunused-parameter -Wunreachable-code -Wall -std=c++11"),
-        QStringLiteral("-ferror-limit=100 -fspell-checking -Wdocumentation -Wunused-parameter -Wunreachable-code -Wall -std=CL1.1"),
-        QStringLiteral("-ferror-limit=100 -fspell-checking -Wdocumentation -Wunused-parameter -Wunreachable-code -Wall -std=c++11"),
+        QStringLiteral("-ferror-limit=100 -fspell-checking -Wdocumentation -Wunused-parameter -Wunreachable-code -Wall -Wno-error -std=c99"),
+        QStringLiteral("-ferror-limit=100 -fspell-checking -Wdocumentation -Wunused-parameter -Wunreachable-code -Wall -Wno-error -std=c++11"),
+        QStringLiteral("-ferror-limit=100 -fspell-checking -Wdocumentation -Wunused-parameter -Wunreachable-code -Wall -Wno-error -std=CL1.1"),
+        QStringLiteral("-ferror-limit=100 -fspell-checking -Wdocumentation -Wunused-parameter -Wunreachable-code -Wall -Wno-error -std=c++11"),
         true
     };
 
diff --git a/plugins/custom-definesandincludes/definesandincludesmanager.cpp b/plugins/custom-definesandincludes/definesandincludesmanager.cpp
--- a/plugins/custom-definesandincludes/definesandincludesmanager.cpp
+++ b/plugins/custom-definesandincludes/definesandincludesmanager.cpp
@@ -356,15 +356,16 @@
 
     Q_ASSERT(QThread::currentThread() == qApp->thread());
 
+    auto cfg = item->project()->projectConfiguration().data();
+    const auto arguments = findConfigForItem(m_settings->readPaths(cfg), item).parserArguments;
+
     auto buildManager = item->project()->buildSystemManager();
     if ( buildManager ) {
         const auto args = buildManager->extraArguments(item);
         if (!args.isEmpty())
-            return args;
+            return args + argumentsForPath(item->path(), arguments);
     }
 
-    auto cfg = item->project()->projectConfiguration().data();
-    const auto arguments = findConfigForItem(m_settings->readPaths(cfg), item).parserArguments;
     return argumentsForPath(item->path(), arguments);
 }