[pdal] make uninstall

[David Burken]

Hi,

I added an uninstall if you want it.  Handy when there are header 
changes and so on.

// Small change to end of CMakeLists.txt:

$ pwd
/work/osgeo/pdal/latest

$ git diff CMakeLists.txt
diff --git a/CMakeLists.txt b/CMakeLists.txt
index c4bb26b..801ec53 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -331,3 +331,7 @@ install(EXPORT PDALTargets DESTINATION lib/pdal/cmake)
  include(${PDAL_CMAKE_DIR}/config.cmake)

  feature_summary(WHAT ALL INCLUDE_QUIET_PACKAGES)
+
+# Add uninstall target:
+add_custom_target( uninstall
+   "${CMAKE_COMMAND}" -P "${CMAKE_MODULE_PATH}/uninstall.cmake" )

// Added one file:
$ pwd
/work/osgeo/pdal/latest/cmake/modules

$ cat uninstall.cmake
#---
# File: pdal uninstall.cmake
#---
set(MANIFEST "${CMAKE_CURRENT_BINARY_DIR}/install_manifest.txt")

if(NOT EXISTS ${MANIFEST})
message(FATAL_ERROR "Cannot find install manifest: '${MANIFEST}'")
endif()

file(STRINGS ${MANIFEST} files)
foreach(file ${files})
if(EXISTS ${file})
message(STATUS "Removing file: '${file}'")

exec_program(
${CMAKE_COMMAND} ARGS "-E remove ${file}"
OUTPUT_VARIABLE stdout
RETURN_VALUE result
)
if(NOT "${result}" STREQUAL 0)
message(FATAL_ERROR "Failed to remove file: '${file}'.")
endif()
else()
MESSAGE(STATUS "File '${file}' does not exist.")
endif()
endforeach(file)


// NOTE1:  This was causing a doubling my CMAKE_MODULE_PATH, as I set 
the path in my cmake line:  e.g.:
/work/osgeo/pdal/latest/cmake/modules;/work/osgeo/pdal/latest/cmake/modules

$ pwd
/work/osgeo/pdal/latest/cmake
$ grep CMAKE_MODULE_PATH *
modules.cmake:set(CMAKE_MODULE_PATH ${PDAL_MODULE_DIR} ${CMAKE_MODULE_PATH})

// NOTE2:
You have a bunch of double '//' in your cmake stuff.  e.g. from make 
install:

-- Installing: /work/osgeo/deps/include//pdal//UserCallback.hpp

Take care,
Dave