Handle CPACK_MONOLITHIC_INSTALL in some rare use cases.

For example, when CPACK_<GEN>_COMPONENT_INSTALL and
CPACK_MONOLITHIC_INSTALL are both set. Previously, this
combination of variable settings produced an error without
any explanation. Now, in this case CPACK_MONOLITHIC_INSTALL wins
without trouble.
This is useful for when e.g. CPACK_ARCHIVE_COMPONENT_INSTALL is
globally on and one wants MONOLITHIC install for STGZ (but not
other generators). The same behavior may be obtained by re-setting
CPACK_ARCHIVE_COMPONENT_INSTALL to 0 but in any case the
'both set' case should have been handled without error.

Source/CPack/cmCPackArchiveGenerator.cxx

@@ -247,7 +247,7 @@ int cmCPackArchiveGenerator::PackageFiles()
   cmCPackLogger(cmCPackLog::LOG_DEBUG, "Toplevel: "
                 << toplevel << std::endl);
 
-  if (SupportsComponentInstallation()) {
+  if (WantsComponentInstallation()) {
     // CASE 1 : COMPONENT ALL-IN-ONE package
     // If ALL COMPONENTS in ONE package has been requested
     // then the package file is unique and should be open here.

Source/CPack/cmCPackDebGenerator.cxx

@@ -236,7 +236,7 @@ int cmCPackDebGenerator::PackageFiles()
   int retval = -1;
 
   /* Are we in the component packaging case */
-  if (SupportsComponentInstallation()) {
+  if (WantsComponentInstallation()) {
     // CASE 1 : COMPONENT ALL-IN-ONE package
     // If ALL GROUPS or ALL COMPONENTS in ONE package has been requested
     // then the package file is unique and should be open here.

Source/CPack/cmCPackGenerator.cxx

@@ -1436,6 +1436,12 @@ bool cmCPackGenerator::SupportsComponentInstallation() const
   return false;
 }
 
+//----------------------------------------------------------------------
+bool cmCPackGenerator::WantsComponentInstallation() const
+{
+  return (!IsOn("CPACK_MONOLITHIC_INSTALL") & SupportsComponentInstallation());
+}
+
 //----------------------------------------------------------------------
 cmCPackInstallationType*
 cmCPackGenerator::GetInstallationType(const char *projectName,

Source/CPack/cmCPackGenerator.h

@@ -189,7 +189,21 @@ protected:
   virtual int InstallProjectViaInstallCMakeProjects(
     bool setDestDir, const char* tempInstallDirectory);
 
+  /**
+   * Does the CPack generator support component installation?.
+   * Some Generators requires the user to set
+   * CPACK_<GENNAME>_COMPONENT_INSTALL in order to make this
+   * method return true.
+   * @return true if supported, false otherwise
+   */
   virtual bool SupportsComponentInstallation() const;
+  /**
+   * Does the currently running generator want a component installation.
+   * The generator may support component installation but he may
+   * be requiring monolithic install using CPACK_MONOLITHIC_INSTALL.
+   * @return true if component installation is supported and wanted.
+   */
+  virtual bool WantsComponentInstallation() const;
   virtual cmCPackInstallationType* GetInstallationType(const char *projectName,
                                                        const char* name);
   virtual cmCPackComponent* GetComponent(const char *projectName,

Source/CPack/cmCPackRPMGenerator.cxx

@@ -201,7 +201,7 @@ int cmCPackRPMGenerator::PackageFiles()
                   << toplevel << std::endl);
 
   /* Are we in the component packaging case */
-  if (SupportsComponentInstallation()) {
+  if (WantsComponentInstallation()) {
     // CASE 1 : COMPONENT ALL-IN-ONE package
     // If ALL COMPONENTS in ONE package has been requested
     // then the package file is unique and should be open here.