add pkg-config

Author: mtrezza

Gemfile

@@ -5,3 +5,4 @@ gem 'naturally', '~> 1.3.2'
 gem 'jazzy', '~> 0.13.5'
 gem 'xcpretty'
 gem 'rake'
+gem 'pkg-config'

Gemfile.lock

@@ -85,6 +85,7 @@ GEM
     naturally (1.3.2)
     netrc (0.11.0)
     open4 (1.3.4)
+    pkg-config (1.5.1)
     plist (3.6.0)
     public_suffix (4.0.7)
     rake (13.0.6)
@@ -119,6 +120,7 @@ PLATFORMS
 DEPENDENCIES
   jazzy (~> 0.13.5)
   naturally (~> 1.3.2)
+  pkg-config
   plist
   rake
   xcpretty