Merge pull request #137 from williamdes/patch-1

Add alpine linux apk add

Author: sdroege

src/lib.rs

@@ -175,7 +175,8 @@ impl fmt::Display for Error {
                             "Try `brew install pkg-config` if you have Homebrew.\n"
                         } else if cfg!(unix) {
                             "Try `apt install pkg-config`, or `yum install pkg-config`,\n\
-                            or `pkg install pkg-config` depending on your distribution.\n"
+                            or `pkg install pkg-config`, or `apk add pkgconfig` \
+                            depending on your distribution.\n"
                         } else {
                             "" // There's no easy fix for Windows users
                         };