Remove trailing whitespace from most CMake and C/C++ code

Our Git commit hooks disallow modification or addition of lines with
trailing whitespace.  Wipe out all remnants of trailing whitespace
everywhere except third-party code.

Run the following shell code:

git ls-files -z -- \
 bootstrap doxygen.config '*.readme' \
 '*.c' '*.cmake' '*.cpp' '*.cxx' \
 '*.el' '*.f' '*.f90' '*.h' '*.in' '*.in.l' '*.java' \
 '*.mm' '*.pike' '*.py' '*.txt' '*.vim' |
egrep -z -v '^(Utilities/cm|Source/(kwsys|CursesDialog/form)/)' |
egrep -z -v '^(Modules/CPack\..*\.in)' |
xargs -0 sed -i 's/ \+$//'

CMakeCPackOptions.cmake.in

@@ -1,6 +1,6 @@
 # This file is configured at cmake time, and loaded at cpack time.
 # To pass variables to cpack from cmake, they must be configured
-# in this file.  
+# in this file.
 
 if(CPACK_GENERATOR MATCHES "NSIS")
   SET(CPACK_NSIS_INSTALL_ROOT "@CPACK_NSIS_INSTALL_ROOT@")
@@ -45,9 +45,9 @@ if(CPACK_GENERATOR MATCHES "CygwinSource")
 endif(CPACK_GENERATOR MATCHES "CygwinSource")
 
 if("${CPACK_GENERATOR}" STREQUAL "PackageMaker")
-  if(CMAKE_PACKAGE_QTGUI)                       
+  if(CMAKE_PACKAGE_QTGUI)
     set(CPACK_PACKAGE_DEFAULT_LOCATION "/Applications")
-  else(CMAKE_PACKAGE_QTGUI)                     
+  else(CMAKE_PACKAGE_QTGUI)
     set(CPACK_PACKAGE_DEFAULT_LOCATION "/usr")
-  endif(CMAKE_PACKAGE_QTGUI)                    
+  endif(CMAKE_PACKAGE_QTGUI)
 endif("${CPACK_GENERATOR}" STREQUAL "PackageMaker")