BundleUtilities: Use find on UNIX for fast executable lookup

It makes whole executable process quicker on UNIX, especially for large bundles
containing many files, since using find narrows results to only files having
executable flags then all further tests follow.

Since find ... -perm +0111 is not clearly POSIX compliant and some Linux
versions refuse it, it is better to use longer but portable:

   find ... -perm \( -perm -0100 -o -perm -0010 -o -perm -0001 \)
GetPrerequisites: Make sure dyld placeholders are prefixes

Mac OS X dyld placeholders should be always prefixes, otherwise this can lead
to some undefined behavior.
BundleUtilities: Resolve & replace @rpath placeholders

This is done by gathering LC_RPATH commands for main bundle executable and
using it for @rpath lookup in dependent frameworks.

All functions that need to carry rpaths to now take optional <rpaths> argument.

This enabled apps using @rpath to be bundled correctly, which will be necessary
for upcoming Qt 5.4 that will use @rpath for all frameworks.

Check that install_name_tool has -delete_rpath before using it.
Otherwise it will fail with Xcode 3.x on 10.5 which has no -delete_rpath
option for install_name_tool command, that was first introduced in 10.6
SDK, even that 10.5 supports LC_RPATH and @rpath.
BundleUtilities: Framework codesign Resources/Info.plist & Current

We need to ensure copied framework has proper layout with Resources/Info.plist
present next to versioned binary and Current symlink in Versions:

https://developer.apple.com/library/mac/technotes/tn2206

https://developer.apple.com/library/mac/documentation/MacOSX/Conceptual/BPFrameworks/Concepts/FrameworkAnatomy.html

If Resources/ is not present we may try to copy Contents/Info.plist if present
to embedded Resources/Info.plist. This is a case of Qt5 that has
obsolete/invalid framework layout (see QTBUG-38511).
cmake-gui: Make sure we bundle Qt5 Cocoa platform plugin

Otherwise CMake.app bundle will not run when using Qt5.
OSX: Warn when attempting to change runtime paths on OS X 10.5

Even though 10.5 supports @rpath, the support is not complete
enough for CMake.  For instance, install_name_tool doesn't support
adding and removing rpaths.

Also modifying BundleUtilities test to remove an undesirable cmake
generated runtime path.  The intent was to build with the install
rpath as is done with the other cases in this test.
Merge topic 'fix-OSX-bundle-rpaths-and-Qt5' into next

50e261dd OSX: Warn when attempting to change runtime paths on OS X 10.5
9b98fd52 cmake-gui: Make sure we bundle Qt5 Cocoa platform plugin
83a06bb4 BundleUtilities: Framework codesign Resources/Info.plist & Current
f7df82ac BundleUtilities: Resolve & replace @rpath placeholders
14bc686f GetPrerequisites: Make sure dyld placeholders are prefixes
6c313797 BundleUtilities: Use find on UNIX for fast executable lookup