file-browser-applet in tree introduced support for Super-H hotkey for menu activation via gtkhotkey library in 0.5.8. The dependency was optional:crazy: but automagic and the build system of the package is cmake. After examining Diego’s documentation for general information and personally getting help from him, I researched for how to fix the issue for cmake. You can see the bug report and my initial patch for the package. After releasing 2 more versions following 0.5.8 a modified version of my patch is committed. The upstream patch still prints out an ugly not found error even if file-browser-applet is compiled with -gtkhotkey. But I bumped and added the upstream patch to portage.
What I learned from this is cmake has an interesting if-then-else syntax that you need to include the control variable near each keyword. What I need to do afterwards is to extend Diego’s documentation with a paragraph about cmake.
Edit: I added prelimenary CMake section to Diego’s documentation. Please extend it with different possibilities which CMake may cause automagic dependencies.