Merge pull request #2924 from sjackman/sse4-linux

cpu: fix SSE4 detection on Linux

Library/Homebrew/extend/os/linux/hardware/cpu.rb

@@ -84,7 +84,7 @@ module Hardware
         @features ||= flags[1..-1].map(&:intern)
       end
 
-      %w[aes altivec avx avx2 lm ssse3 sse4 sse4_2].each do |flag|
+      %w[aes altivec avx avx2 lm ssse3 sse4_2].each do |flag|
         define_method(flag + "?") { flags.include? flag }
       end
 
@@ -92,6 +92,10 @@ module Hardware
         flags.include?("pni") || flags.include?("sse3")
       end
 
+      def sse4?
+        flags.include? "sse4_1"
+      end
+
       alias is_64_bit? lm?
 
       def bits