title: How to build Qt with custom compiler and custom flags?
body: <p>I am building Qt 5.4 and I want to use my custom built <code>GCC</code> version which is different from the system one. I don't want to replace system <code>GCC</code> with my one. However, I don't see how can I alter the compiler absolute path that the Qt build system uses, as well as how to add custom flags. Usually open source libraries use <code>CXX</code> and <code>CXXFLAGS</code> variables to alter compiler absolute path and its options, but it looks like Qt build system ignores these variables.</p>
  
  <p>Does Qt 5.4 build system have any options similar to common for GNU projects <code>CXX</code> and <code>CXXFLAGS</code>, as well as <code>LD</code> and <code>LDFLAGS</code>?</p>