poppler: Support building against QT4-embedded

These changes allow the poppler package to build using qt4e.
To enable them, add this line to local.conf
  PACKAGECONFIG_append_pn-poppler = " qt4e"

Signed-off-by: Gary Thomas <gary@mlbassoc.com>
Upstream-status: Innapropriate [OE configuration]
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>