update MacOS installation instructions

see https://github.com/dannyedel/dspdfviewer/issues/174
for the motivation

diff --git a/installation/macos.md b/installation/macos.md
index 1a813f1668b3483a30cdaa3ad938dd2bb3fab878..4c738f1f7605406872d35762a962f44d3bfc581e 100644 (file)
--- a/installation/macos.md
+++ b/installation/macos.md
@@ -3,7 +3,7 @@ title: Installation on MacOS
 layout: default
 ---
 
-## Homebrew
+## Homebrew (recommended)
 If you use a mac with Homebrew, there already is a formula to install
 dspdfviewer
 
@@ -17,3 +17,16 @@ newest features, provide the head option:
 {% highlight bash %}
 brew install dspdfviewer --HEAD
 {% endhighlight %}
+
+## Manually (advanced users)
+
+If you want to compile from source, please read the
+[generic install instructions](/installation/) about
+the available cmake-time switches.
+
+If you installed Qt5 via Homebrew, you will have
+to pass its installation prefix to `cmake`:
+
+```bash
+cmake /path/to/source -DSomeOption=ON -DCMAKE_PREFIX_PATH=$(brew --prefix qt5)
+```