diff --git a/lib/timeout_interrupt.rb b/lib/timeout_interrupt.rb
index 5c46ff8..438783a 100644
--- a/lib/timeout_interrupt.rb
+++ b/lib/timeout_interrupt.rb
@@ -1,23 +1,6 @@
 require 'ffi/libc'
 require 'timeout'
 
-# Provided by ffi-libc-lib and extended by this library, if needed.
-# Older version of ffi-libc does not provide {FFI::LibC.alarm}
-module FFI
-	module LibC
-		# @!method alarm(seconds)
-		# Sets an alarm. After `seconds` it will send an ALRM-signal to this process.
-		#
-		# Predefined alarm will be reset and will forget.
-		# @note Older implementations of ffi-libc does not provide {alarm}, but we need it.
-		#       So we detect, if it is not provided and attach it.
-		# @param seconds [0] Clears alarm.
-		# @param seconds [Integer] How many seconds should be waited, before ALRM-signal should be send?
-		# @return (nil)
-		attach_function :alarm, [:uint], :uint  unless FFI::LibC.respond_to? :alarm
-	end
-end
-
 # Helper module for `TimeoutInterrupt`
 # @see TimeoutInterrupt
 module TimeoutInterruptSingleton
diff --git a/timeout-interrupt.gemspec b/timeout-interrupt.gemspec
index ccdc70e..bbe276e 100644
--- a/timeout-interrupt.gemspec
+++ b/timeout-interrupt.gemspec
@@ -26,5 +26,5 @@ Gem::Specification.new do |spec|
 	spec.require_paths = ["lib"]
 	spec.require_paths = ["lib"]
 
-	spec.add_runtime_dependency %q<ffi-libc>
+	spec.add_runtime_dependency %q<ffi-libc>, '>= 0.1.1'
 end