Concise --config output for build errors

Rationale, lets only pay attention to the output when it matters. Speeding up diagnosis.

Library/Homebrew/cmd/--config.rb

@@ -76,14 +76,41 @@ module Homebrew extend self
     Pathname.new(a_path).realpath.to_s
   end
 
+  def hardware
+    "CPU: #{Hardware.cores_as_words}-core #{Hardware.bits}-bit #{Hardware.intel_family}"
+  end
+
+  def kernel
+    `uname -m`.chomp
+  end
+
+  # we try to keep output minimal
+  def dump_build_config
+    puts "HOMEBREW_PREFIX: #{HOMEBREW_PREFIX}" if HOMEBREW_PREFIX.to_s != "/usr/local"
+    puts "HOMEBREW_CELLAR: #{HOMEBREW_CELLAR}" if HOMEBREW_CELLAR.to_s != "#{HOMEBREW_PREFIX}/Cellar"
+    puts hardware
+    puts "MacOS: #{MACOS_FULL_VERSION}-#{kernel}"
+    puts "Xcode: #{xcode_version}"
+    puts "/usr/bin/ruby: #{RUBY_VERSION}-#{RUBY_PATCHLEVEL}" if RUBY_VERSION.to_f != 1.8
+
+    ruby = Pathname.new("/usr/bin/ruby")
+    puts "/usr/bin/ruby => #{ruby.realpath}" unless ruby.realpath.to_s =~ %r{^/System}
+
+    ponk = macports_or_fink_installed?
+    puts "MacPorts/Fink: #{ponk?}" if ponk
+
+    x11 = describe_x11
+    puts "X11: #{x11}" unless x11 == "/usr/X11"
+  end
+
   def config_s; <<-EOS.undent
     HOMEBREW_VERSION: #{HOMEBREW_VERSION}
     HEAD: #{sha}
     HOMEBREW_PREFIX: #{HOMEBREW_PREFIX}
     HOMEBREW_CELLAR: #{HOMEBREW_CELLAR}
-    Hardware: #{Hardware.cores_as_words}-core #{Hardware.bits}-bit #{Hardware.intel_family}
+    #{hardware}
     OS X: #{MACOS_FULL_VERSION}
-    Kernel Architecture: #{`uname -m`.chomp}
+    Kernel Architecture: #{kernel}
     Xcode: #{xcode_version}
     GCC-4.0: #{gcc_40 ? "build #{gcc_40}" : "N/A"}
     GCC-4.2: #{gcc_42 ? "build #{gcc_42}" : "N/A"}

Library/Homebrew/exceptions.rb

@@ -98,17 +98,17 @@ class BuildError < Homebrew::InstallationError
       issues_url = ISSUES_URL
     end
 
-    ohai "Exit Status: #{e.exit_status}"
-    puts "https://github.com/#{repo}/blob/master/#{repo_path}/#{formula_name}.rb#L#{error_line}"
-    ohai "Environment"
-    puts Homebrew.config_s
-    ohai "Build Flags"
+    if ARGV.verbose?
+      ohai "Exit Status: #{e.exit_status}"
+      puts "https://github.com/#{repo}/blob/master/#{repo_path}/#{formula_name}.rb#L#{error_line}"
+    end
+    ohai "Build Environment"
+    Homebrew.dump_build_config
     puts %["--use-clang" was specified] if ARGV.include? '--use-clang'
     puts %["--use-llvm" was specified] if ARGV.include? '--use-llvm'
     puts %["--use-gcc" was specified] if ARGV.include? '--use-gcc'
     Homebrew.dump_build_env e.env
-    puts
-    onoe e
+    onoe "#{e.to_s.strip} (#{formula_name}.rb:#{error_line})"
     issues = GitHub.issues_for_formula formula_name
     if issues.empty?
       puts "If `brew doctor' does not help diagnose the issue, please report the bug:"