title: Global environment variables in vscode
body: <p>I have c_cpp_properties.json, launch.json, and tasks.json in my project. There are some strings that I use common between them. Is there a way that I can define an environment variable then use it in all three files</p>
  <p>For instance, in c_cpp_properties.json I have:</p>
  <pre><code>&quot;compilerPath&quot;: &quot;/some/path/to/sysroots/x86_64-petalinux-linux/usr/bin/aarch64-xilinx-linux/aarch64-xilinx-linux-g++&quot;
  </code></pre>
  <p>In tasks.json I have:</p>
  <pre><code>&quot;command&quot;: &quot;/some/path/to/sysroots/x86_64-petalinux-linux/usr/bin/aarch64-xilinx-linux/aarch64-xilinx-linux-g++ --sysroot=/some/path/to/sysroots/aarch64-xilinx-linux -g test.cpp -o build/test&quot;
  </code></pre>
  <p>In launch.json I have:</p>
  <pre><code>&quot;miDebuggerPath&quot;: &quot;/some/path/to/sysroots/x86_64-petalinux-linux/usr/bin/aarch64-xilinx-linux/aarch64-xilinx-linux-gdb&quot;
  </code></pre>
  <p>I want to just define &quot;${sysroots} = /some/path/to/sysroots&quot; once, then just use that variable in all three files. That way if I have to change it, I only need to change it in one place. This seems like pretty obvious functionality. Am I missing something?</p>