Molti problemi con Homebrew

Questa è probabilmente una cattiva forma per questa scheda e sentiti libero di eliminarla se lo è, ma l'esecuzione brew doctorrivela quanto segue:

Warning: /usr/local/lib/pkgconfig isn't writable.
This can happen if you "sudo make install" software that isn't managed
by Homebrew.

If a brew tries to write a .pc file to this directory, the install will
fail during the link step.

You should probably `chown` /usr/local/lib/pkgconfig
Warning: "config" scripts exist outside your system or Homebrew directories.
`./configure` scripts often look for *-config scripts to determine if
software packages are installed, and what additional flags to use when
compiling and linking.

Having additional scripts in your path can confuse software installed via
Homebrew if the config script overrides a system or Homebrew provided
script of the same name. We found the following "config" scripts:

/opt/local/bin/freetype-config
/opt/local/bin/libpng-config
/opt/local/bin/libpng15-config
/opt/local/bin/Magick++-config
/opt/local/bin/Magick-config
/opt/local/bin/MagickCore-config
/opt/local/bin/MagickWand-config
/opt/local/bin/ncurses5-config
/opt/local/bin/ncursesw5-config
/opt/local/bin/pkg-config
/opt/local/bin/python2-config
/opt/local/bin/python2.7-config
/opt/local/bin/Wand-config
/opt/local/bin/xml2-config
/Users/Paul/.rvm/gems/ruby-1.9.3-p194/bin/passenger-config
/Library/Frameworks/Python.framework/Versions/2.7/bin/python-config
/Library/Frameworks/Python.framework/Versions/2.7/bin/python2-config
/Library/Frameworks/Python.framework/Versions/2.7/bin/python2.7-config

Warning: /Library/Frameworks/Mono.framework detected
This can be picked up by CMake's build system and likely cause the build to
fail. You may need to move this file out of the way to compile CMake.
Warning: You have Macports or Fink installed.
This can cause trouble. You don't have to uninstall them, but you may like to
try temporarily moving them away, eg.

  sudo mv /opt/local ~/macports

Warning: Your Homebrew is outdated
You haven't updated for at least 24 hours, this is a long time in brewland!
Warning: You have leftover files from an older version of Xcode.
You should delete them using:
  Developer/Library/uninstall-developer-folder

Warning: Unbrewed dylibs were found in /usr/local/lib.
If you didn't put them there on purpose they could cause problems when
building Homebrew formulae, and may need to be deleted.


    Unexpected dylibs:
    /usr/local/lib/libFLAC++.2.1.2.dylib    /usr/local/lib/libFLAC++.2.dylib                          /usr/local/lib/libFLAC++.dylib    /usr/local/lib/libFLAC.4.1.2.dylib    /usr/local/lib/libFLAC.4.dylib    /usr/local/lib/libFLAC.dylib    /usr/local/lib/libguide.dylib    /usr/local/lib/libmacfuse_i32.2.dylib    /usr/local/lib/libmacfuse_i64.2.dylib    /usr/local/lib/libosxfuse_i32.2.dylib    /usr/local/lib/libosxfuse_i64.2.dylib    /usr/local/lib/libusb-1.0.0.dylib
Warning: Unbrewed .la files were found in /usr/local/lib.
If you didn't put them there on purpose they could cause problems when
building Homebrew formulae, and may need to be deleted.

Unexpected .la files:
    /usr/local/lib/libFLAC++.la    /usr/local/lib/libFLAC.la    /usr/local/lib/libosxfuse_i32.la    /usr/local/lib/libosxfuse_i64.la
Warning: Unbrewed .pc files were found in /usr/local/lib/pkgconfig.
If you didn't put them there on purpose they could cause problems when
building Homebrew formulae, and may need to be deleted.

Unexpected .pc files:
    /usr/local/lib/pkgconfig/osxfuse.pc
Warning: Unbrewed static libraries were found in /usr/local/lib.
If you didn't put them there on purpose they could cause problems when
building Homebrew formulae, and may need to be deleted.

Unexpected static libraries:
    /usr/local/lib/libFLAC++.a    /usr/local/lib/libFLAC.a
Warning: Suspicious Git newline settings found.

The detected Git newline settings can cause checkout problems:
  core.autocrlf = input
  core.safecrlf = true

If you are not routinely dealing with Windows-based projects,
consider removing these settings.
Warning: You have uncommitted modifications to Homebrew
If this a surprise to you, then you should stash these modifications.
Stashing returns Homebrew to a pristine state but can be undone
should you later need to do so for some reason.
    cd /usr/local/Library && git stash && git clean -f
Error: Homebrew doesn't know what compiler versions ship with your version of
Xcode. Please file an issue with the output of `brew --config`:
  https://github.com/mxcl/homebrew/issues

Thanks!
Warning: /usr/bin occurs before /usr/local/bin
This means that system-provided programs will be used instead of those
provided by Homebrew. The following tools exist at both paths:

    2to3
    2to3-2.7
    idle
    idle2.7
    pydoc
    pydoc2.7
    python
    python-config
    python2.7
    python2.7-config
    pythonw
    pythonw2.7
    smtpd.py
    smtpd2.7.py

Consider amending your PATH so that /usr/local/bin
occurs before /usr/bin in your PATH.
Warning: You have a non-Homebrew 'pkg-config' in your PATH:
  /usr/bin/pkg-config => /Library/Frameworks/Mono.framework/Versions/2.10.8/bin/pkg-config

This was most likely created by the Mono installer. `./configure` may
have problems finding brew-installed packages using this other pkg-config.

Non so nemmeno da dove cominciare. So abbastanza di questo genere di cose da eseguire brew doctore forse correggere un errore di autorizzazioni, ma questo è semplicemente travolgente.

Qualsiasi aiuto su quale di questi errori è importante, che posso ignorare, i problemi che potrei avere con altri programmi se li "correggessi", sarebbero apprezzati.

Ho usato solo MacPorts per installare Image Magick e probabilmente non avrei potuto usarlo altrimenti, e non ho idea del perché ho il Mono Framework. Non ho intenzione di diventare uno sviluppatore iOS presto.