override rwxr-xr-x  root/wheel for /usr/local/lib/libpng.3.dylib? brew doctor
chochocho-MacBook-Pro:macports fujiutomoko$ brew doctor
Warning: Your Homebrew is outdated
You haven't updated for at least 24 hours, this is a long time in brewland!
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/libjpeg.8.dylib    /usr/local/lib/libpng.3.dylib    /usr/local/lib/libpng12.0.dylib    /usr/local/lib/libpng14.14.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/libjpeg.la    /usr/local/lib/libpng12.la    /usr/local/lib/libpng14.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/libpng12.pc    /usr/local/lib/pkgconfig/libpng14.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/libjpeg.a    /usr/local/lib/libpng12.a    /usr/local/lib/libpng14.a
Warning: You have unlinked kegs in your Cellar
Leaving kegs unlinked can lead to build-trouble and cause brews that depend on
those kegs to fail to run properly once built. Run `brew link` on these:

    git
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
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:

    svn
    svnadmin
    svndumpfilter
    svnlook
    svnserve
    svnsync
    svnversion

Consider amending your PATH so that /usr/local/bin
occurs before /usr/bin in your PATH.