Bug 10444

Hello Scott,

It's not documented how line joining works. This is mostly stuff that people
figure out quickly anyway, but it doesn't hurt to cover it in some detail.

Here's a suggested new section:

  3.1.2. Line joining
  
  Outside of
  [functions](https://www.yoctoproject.org/docs/2.2/bitbake-user-manual/bitbake-user-manual.html#functions)
  , BitBake joins any line ending in "\" with the following line before parsing
  statements. This is most commonly used to split variable assignments over
  multiple lines, as in the following example:
  
    FOO = "bar \
           baz \
           qaz"
  
  Both the backslash and the newline that follows it are removed when joining
  lines, so no newlines end up in the value of FOO. As another example, the two
  assignments below both assign "barbaz" to FOO:
  
    FOO = "barbaz"
  
    FOO = "bar\
    baz"
  
  Note {
  BitBake does not interpet escape sequences like '\n' in variable values. For
  these to have an effect, the value must be passed to some utility that
  interprets escape sequences, like 'printf' or 'echo -n'.
  }


Cheers,
Ulf