The newly released gdk-pixbuf 2.32.0 forces relocation during the compilation process, which is only really useful when you plan on putting gdk-pixbuf into an app bundle.

If however, the user installs gdk-pixbuf through one of Mac OS X's package managers like Homebrew, MacPorts or Fink (which is what the vast majority of users of gdk-pixbuf on this platform will do), it is guaranteed to break a lot of packages from running properly as the loaders.cache file will never be found.

This is especially true for Homebrew (of which I am a contributor), which uses a unique installation prefix for every installed package like 

  /usr/local/Cellar/sofware-name/software-version

which is then soft-linked into /usr/local. Since the location of loaders.cache is determined relative to the executable path, loaders.cache will never get found.

Even MacPorts, though it uses a single installation prefix for all its packages, patched gdk-pixbuf to remove relocation. This is because it breaks software written in python that uses gtk+3, in which case the effective executable is hidden somewhere deep within the Python Framework, which will certainly lead to loaders.cache not being found. 

This is the first error message I get running meld for example (with Homebrew):

(meld:33141): GdkPixbuf-WARNING **: Cannot open pixbuf loader module file '/usr/local/Cellar/python/2.7.10_2/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/../lib/gdk-pixbuf-2.0/2.10.0/loaders.cache': No such file or directory

This likely means that your installation is broken.
Try running the command
  gdk-pixbuf-query-loaders > /usr/local/Cellar/python/2.7.10_2/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/../lib/gdk-pixbuf-2.0/2.10.0/loaders.cache
to make things work again for the time being.


I also think that your relocation path on Mac OS X is not useful even when the goal is to put gdk-pixbuf into an app bundle since the convention is to put additional libraries into Contents/Resources (see gedit.app for an example), which would again lead to loaders.cache not being found at runtime.

May I suggest to incorporate the patch provided by the MacPorts developers at https://trac.macports.org/browser/trunk/dports/graphics/gdk-pixbuf2/files/patch-configure.ac.diff which turns relocation off by default on Mac OS X, while still allowing to be enabled for those that want to?