Update README

README.md

@@ -172,6 +172,11 @@ There are instructions in their repository but it's roughly the following:
 - Run `./configure`
 - Run `make install`
 
+If you're on Debian, this is available in the repositories:
+```
+sudo apt install libgoogle-perftools-dev
+```
+
 #### graphviz
 Graphviz is needed to use `dot`.
 With `apt`: