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/ \+$//'

Source/cmBuildNameCommand.cxx

@@ -25,7 +25,7 @@ bool cmBuildNameCommand
   const char* cacheValue = this->Makefile->GetDefinition(args[0].c_str());
   if(cacheValue)
     {
-    // do we need to correct the value? 
+    // do we need to correct the value?
     cmsys::RegularExpression reg("[()/]");
     if (reg.find(cacheValue))
       {
@@ -41,7 +41,7 @@ bool cmBuildNameCommand
     return true;
     }
 
-  
+
   std::string buildname = "WinNT";
   if(this->Makefile->GetDefinition("UNIX"))
     {
@@ -67,7 +67,7 @@ bool cmBuildNameCommand
                                "(", "_");
   cmSystemTools::ReplaceString(buildname,
                                ")", "_");
-  
+
   this->Makefile->AddCacheDefinition(args[0].c_str(),
                                  buildname.c_str(),
                                  "Name of build.",