Merged revisions 179807 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.4

I had some work to do to port these changes to trunk; the 
check_expr stuff hasn't been updated here for quite some
time, it appears. I added some more tests to the check_expr2
suite. I had to play around with the makefile a bit, etc.

I added STANDALONE2 #ifdefs to ast_expr2.y so as not to
conflict structure with aelparse.

........
  r179807 | murf | 2009-03-03 11:11:34 -0700 (Tue, 03 Mar 2009) | 19 lines
  
  These changes allow AEL to better check ${} constructs within $[...], that are concatenated with text.
  
  I modified and added rules in ast_expr2.fl to better handle
  the concatenations.
  
  I added some default routines to ast_expr2.y so the standalone would
  compile. It also looks like I haven't run this thru bison since 2.1, so
  it's good to get this updated.
  
  The Makefile has comments added now for check_expr2 and check_expr to
  explain what they are for, and how to run them. 
  
  The testexpr2s stuff has been removed, in favor of check_expr2.
  
  expr2.testinput has been updated to include the two expressions
  that inspired these changes (from mcnobody on #asterisk this morning)
  The regression has been run and all looks well.
........


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@179973 65c4cc65-6c06-0410-ace0-fbb531ad65f3