Clean up inreplace regexps

- use literal syntax
 - escape interpolated variables
 - remove intermediate variables
 - remove unnecessary capture

Library/Homebrew/extend/string.rb

@@ -69,22 +69,23 @@ module StringInreplaceExtension
   # value with "new_value", or removes the definition entirely.
   def change_make_var! flag, new_value
     new_value = "#{flag}=#{new_value}"
-    sub = gsub! Regexp.new("^#{flag}[ \\t]*=[ \\t]*(.*)$"), new_value, false
-    opoo "inreplace: changing '#{flag}' to '#{new_value}' failed" if sub.nil?
+    unless gsub!(/^#{Regexp.escape(flag)}[ \t]*=[ \t]*(.*)$/, new_value, false)
+      opoo "inreplace: changing '#{flag}' to '#{new_value}' failed"
+    end
   end
 
   # Removes variable assignments completely.
   def remove_make_var! flags
     Array(flags).each do |flag|
       # Also remove trailing \n, if present.
-      sub = gsub! Regexp.new("^#{flag}[ \\t]*=(.*)$\n?"), "", false
-      opoo "inreplace: removing '#{flag}' failed" if sub.nil?
+      unless gsub!(/^#{Regexp.escape(flag)}[ \t]*=.*$\n?/, "", false)
+        opoo "inreplace: removing '#{flag}' failed"
+      end
     end
   end
 
   # Finds the specified variable
   def get_make_var flag
-    m = match Regexp.new("^#{flag}[ \\t]*=[ \\t]*(.*)$")
-    return m[1] if m
+    self[/^#{Regexp.escape(flag)}[ \t]*=[ \t]*(.*)$/, 1]
   end
 end