Running with CLT but without Xcode

[GoogleCodeExporter]

What steps will reproduce the problem?
1. On a new machine - install Xcode Command-Line Tools (CLT) only, but don't 
install full xcode
2. try to perform diff 
3.

What is the expected output? What do you see instead?
- It should run FileMerge, however xcrun returns an error "xcrun: Error: failed 
to exec real xcrun. (No such file or directory)"

What version of the product are you using? On what operating system?
1.3.4 on OSX 10.8.2

Please provide any additional information below.
- Apparently, xcrun has problems running with only CLT. 
(see also :
  [1] :  http://stackoverflow.com/questions/13041525/osx-10-8-xcrun-no-such-file-or-directory
  [2] :  http://stackoverflow.com/questions/11977648/xcrun-error-failed-to-exec-real-xcrun-no-such-file-or-directory
)

So although all the files are there (i.e., FileMerge DOES exists and is 
accessible), xcrun doesn't work well and doesn't run FileMerge. 

Original issue reported on code.google.com by RanGel...@gmail.com on 22 Nov 2012 at 8:05

[GoogleCodeExporter]

Really?  Where are the real opendiff & FileMerge.app installed if you only 
install the CLTs?
Have you tried replacing /usr/bin/opendiff with a symlink to the real opendiff?
Have you tried setting $DEVELOPER_DIR?  (See man xcrun.)

It would be great if Apple shipped FileMerge.app with the base OS.  But I’m 
not holding my breath.

Original comment by chris...@gmail.com on 23 Nov 2012 at 1:16