libevent: fix some strict audit failures.

Formula/libevent.rb

@@ -1,5 +1,3 @@
-require "formula"
-
 class Libevent < Formula
   homepage "http://libevent.org"
   url "https://github.com/downloads/libevent/libevent/libevent-2.0.21-stable.tar.gz"
@@ -22,24 +20,28 @@ class Libevent < Formula
     depends_on "libtool" => :build
   end
 
-  depends_on "doxygen" => :build if build.include? "enable-manpages"
+  depends_on "doxygen" => [:optional, :build]
   depends_on "pkg-config" => :build
   depends_on "openssl"
 
   option :universal
-  option "enable-manpages", "Install the libevent manpages (requires doxygen)"
+  option "with-doxygen", "Build and install the manpages (using Doxygen)"
+
+  deprecated_option "enable-manpages" => "with-doxygen"
 
   fails_with :llvm do
     build 2326
     cause "Undefined symbol '_current_base' reported during linking."
   end
 
-  # Enable manpage generation
-  patch :DATA if build.include? "enable-manpages"
-
   def install
     ENV.universal_binary if build.universal?
     ENV.j1
+
+    if build.with? "doxygen"
+      inreplace "Doxyfile", /GENERATE_MAN\s*=\s*NO/, "GENERATE_MAN = YES"
+    end
+
     system "./autogen.sh" if build.head?
     system "./configure", "--disable-dependency-tracking",
                           "--disable-debug-mode",
@@ -47,24 +49,9 @@ class Libevent < Formula
     system "make"
     system "make", "install"
 
-    if build.include? "enable-manpages"
-      system "make doxygen"
+    if build.with? "doxygen"
+      system "make", "doxygen"
       man3.install Dir["doxygen/man/man3/*.3"]
     end
   end
 end
-
-__END__
-diff --git a/Doxyfile b/Doxyfile
-index 5d3865e..1442c19 100644
---- a/Doxyfile
-+++ b/Doxyfile
-@@ -175,7 +175,7 @@ LATEX_HIDE_INDICES     = NO
- # If the GENERATE_MAN tag is set to YES (the default) Doxygen will 
- # generate man pages
- 
--GENERATE_MAN           = NO
-+GENERATE_MAN           = YES
- 
- # The MAN_EXTENSION tag determines the extension that is added to 
- # the generated man pages (default is the subroutine's section .3)