CppTools: Add reset function to CompilerOptionsBuilder

It makes it easier two get different options.

Task-number: QTCREATORBUG-21693
Change-Id: Ibcfa52d8bbbdf971a38fb6102a6b79e037a9cf02
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

src/plugins/cpptools/compileroptionsbuilder.cpp

@@ -626,4 +626,9 @@ UseToolchainMacros CompilerOptionsBuilder::useToolChainMacros()
                                                                           : UseToolchainMacros::No;
 }
 
+void CompilerOptionsBuilder::reset()
+{
+    m_options.clear();
+}
+
 } // namespace CppTools

src/plugins/cpptools/compileroptionsbuilder.h

@@ -78,6 +78,7 @@ public:
     virtual void addExtraOptions() {}
 
     static UseToolchainMacros useToolChainMacros();
+    void reset();
 
 private:
     bool excludeDefineDirective(const ProjectExplorer::Macro &macro) const;