This version takes to add the include path to the target definition for
cmake 2.8.11 and later. Also the documentation sticks to the existing
convention of using cmake variables ${PROJ4_LIBRARIES} and
${PROJ4_INCLUDE_DIRS}. However, the namespace variables are still being
included.
Here's the roll-out plan
(0) Version 4.9.x: The target is proj and PROJ4_LIBRARIES is set to
this.
(1) Version 5.0.x: Two targets, proj and PROJ4::proj, are defined;
PROJ4_LIBRARIES = proj.
(2) In a year or two: Two targets, proj and PROJ4::proj, are defined;
PROJ4_LIBRARIES = PROJ4::proj.
(3) With a change in the library which breaks backwards compatibility:
The target is PROJ4::proj and PROJ4_LIBRARIES = PROJ4::proj.