title: Unable to compile code using cmath
body: <p>I am attempting to use GLM to work with Vulkan/SDL. I have both of those working correctly, however when I select build, it says that </p>
  
  <pre><code>/usr/include/c++/7.1.1/cmath:45: error: math.h: No such file or directory
   #include_next &lt;math.h&gt;
                 ^~~~~~~~
  </code></pre>
  
  <p>However if I were to go into my project and just include it normally, it works fine. I tried using G++ instead of GCC. I'm on Linux(arch) and using QT Creator QT version 5.9.1 . I'm using Qmake, but no Qt libraries. The GLM code im using is</p>
  
  <pre><code>glm::mat4 matrix;
  glm::vec4 vec;
  auto test = matrix * vec;
  </code></pre>
  
  <p>and these are the includes</p>
  
  <pre><code>#include &lt;vulkan/vulkan.h&gt;
  #include &lt;SDL2/SDL.h&gt;
  #include &lt;glm/vec4.hpp&gt;
  #include &lt;glm/mat4x4.hpp&gt;
  #include &lt;iostream&gt;
  </code></pre>
  
  <p>the compiler command line is:</p>
  
  <pre><code>g++ -c -pipe -std=c++11 -g -std=gnu++11 -Wall -W -fPIC -DQT_QML_DEBUG -I../SDLProject -I. -isystem /usr/local/include -I../VulkanSDK/1.0.54.0/x86_64/include -isystem /usr/include -I/usr/lib/qt/mkspecs/linux-g++ -o main.o ../SDLProject/main.cpp
  </code></pre>