Rakefile in ruby-vpi-21.0.0 vs Rakefile in ruby-vpi-21.1.0

@@ -1,8 +1,12 @@
 # = Environment variables
-# CFLAGS:: Arguments to the compiler.
-# LDFLAGS:: Arguments to the linker.
+#
+# CFLAGS        :: Override the default options passed to the compiler.
+# CFLAGS_EXTRA  :: Provide additional options for the compiler.
+# LDFLAGS       :: Override the default options passed to the linker.
+# LDFLAGS_EXTRA :: Provide additional options for the linker.
+#
 #--
 # Copyright 2006 Suraj N. Kurapati
 # See the file named LICENSE for details.
 
 require 'rake/clean'
@@ -53,12 +57,12 @@
   task :build
 
   directory 'obj'
   CLOBBER.include 'obj'
 
-  ccFlags = ENV['CFLAGS']
-  ldFlags = ENV['LDFLAGS']
+  ccFlags = ENV['CFLAGS_EXTRA']
+  ldFlags = ENV['LDFLAGS_EXTRA']
 
   RubyVPI::SIMULATORS.each do |sim|
     taskName = "build_#{sim.id}"
 
     desc "Builds object files for #{sim.name}."
@@ -66,12 +70,12 @@
       src = RubyVPI::Project[:name] + '.' + Config::CONFIG['DLEXT']
       dst = File.expand_path(File.join('obj', "#{sim.id}.so"))
 
       unless File.exist? dst
         cd 'ext' do
-          ENV['CFLAGS']  = [ccFlags, sim.compiler_args].compact.join(' ')
-          ENV['LDFLAGS'] = [ldFlags, sim.linker_args].compact.join(' ')
+          ENV['CFLAGS_EXTRA']  = [ccFlags, sim.compiler_args].compact.join(' ')
+          ENV['LDFLAGS_EXTRA'] = [ldFlags, sim.linker_args].compact.join(' ')
 
           sh "rake SIMULATOR=#{sim.id}"
           mv src, dst
           sh 'rake clean'
         end
@@ -81,16 +85,17 @@
     task :build => taskName
   end
 
 # documentation
   desc "Build the documentation."
-  task :doc
+  task :doc => 'doc/guide'
 
-  # the user guide
+  desc 'Generate the HTML user guide.'
+  task 'doc/guide' => 'doc/guide.html'
+
   file 'doc/guide.html' => 'doc/guide.erb' do |t|
     sh "gerbil -u html #{t.prerequisites} > #{t.name}"
   end
-  task :doc => 'doc/guide.html'
   CLOBBER.include 'doc/guide.html'
 
 # API reference
   directory 'doc/api'
   CLOBBER.include 'doc/api'