Template directories are Makefile-configured.

src/config.cr.in

@@ -5,6 +5,8 @@ RC_DIRECTORY           = "@SYSCONFDIR@/rc/services"
 LOG_DIRECTORY          = "@VARSTATEDIR@/log"
 SERVICES_DIRECTORY     = "@SHAREDIR@/services"
 ENVIRONMENTS_DIRECTORY = "@SYSCONFDIR@/rc/environments"
+SYSTEM_CONFIGURATION_DIRECTORY = "@SYSCONFDIR@"
+SHARED_DATA_DIRECTORY  = "@SHAREDIR@"
 OWN_LIBEXEC_DIR        = "@LIBEXECDIR@/service"
 CACHE_DIRECTORY        = "@VARSTATEDIR@/cache"
 

src/gen-config.cr

@@ -1,5 +1,7 @@
 require "crinja"
 
+require "./config.cr"
+
 def sanitize_path(path)
 	path.gsub /\/\/+/, "/"
 end
@@ -41,11 +43,9 @@ class Configure::Context
 	def generate(template, target : String, options : Hash(String, String | Array(String) | Crinja::Callable::Instance | Hash(String, String)))
 		target_file = File.open target, "w"
 
-		# FIXME: Alter default sources at build-time.
-		# FIXME: We’ll want a way to alter those context-wide.
 		sources = [
-			"/etc/templates",
-			"/usr/share/templates"
+			"#{SYSTEM_CONFIGURATION_DIRECTORY}/templates",
+			"#{SHARED_DATA_DIRECTORY}/templates"
 		]
 
 		sources = sources