ENH: Add option to disable use of -rpath.

Source/cmUnixMakefileGenerator.cxx

@@ -422,7 +422,7 @@ void cmUnixMakefileGenerator::OutputLinkLibraries(std::ostream& fout,
 
   // concatenate all paths or no?
   bool runtimeConcatenate = ( runtimeSep!="" );
-  if(runtimeFlag == "")
+  if(runtimeFlag == "" || m_Makefile->IsOn("CMAKE_SKIP_RPATH") )
     {
     outputRuntime = false;
     }

Templates/CMakeSystemConfig.cmake.in

@@ -84,6 +84,9 @@ SET (CMAKE_SHLIB_RUNTIME_FLAG "@CMAKE_SHLIB_RUNTIME_FLAG@" CACHE STRING
 SET (CMAKE_SHLIB_RUNTIME_SEP "@CMAKE_SHLIB_RUNTIME_SEP@" CACHE STRING
      "If null, each runtime path is a separate option. Otherwise, they are all joined, separated by this.")
 
+SET (CMAKE_SKIP_RPATH "NO" CACHE BOOL
+     "If set, runtime paths are not added when using shared libraries.")
+
 # support for X11
 
 SET (CMAKE_X_LIBS             "@X_PRE_LIBS@ @X_LIBS@ -lX11 -lXext @X_EXTRA_LIBS@" CACHE STRING 
@@ -149,6 +152,7 @@ CMAKE_MODULE_LINK_FLAGS
 CMAKE_SHLIB_LD_LIBS
 CMAKE_SHLIB_RUNTIME_FLAG
 CMAKE_SHLIB_RUNTIME_SEP
+CMAKE_SKIP_RPATH
 CMAKE_X_CFLAGS
 CMAKE_NO_ANSI_STREAM_HEADERS
 CMAKE_NO_ANSI_FOR_SCOPE