cmake/vtkCompilerExtras: Remove "--no-undefined" gcc linker flag

This commit will help building VTK python wheels by removing the flag
preventing the use of undefined symbol. On Linux (and macOS), the python
symbols are resolved at runtime against the python symbols exposed by
either the python library or the python executable.

Author: jcfr

CMake/vtkCompilerExtras.cmake

@@ -20,11 +20,11 @@ if(CMAKE_COMPILER_IS_GNUCXX)
       set(VTK_EXTRA_SHARED_LINKER_FLAGS "-Wl,--fatal-warnings")
     endif()
     set(CMAKE_SHARED_LINKER_FLAGS
-      "${VTK_EXTRA_SHARED_LINKER_FLAGS} -Wl,--no-undefined -lc ${CMAKE_SHARED_LINKER_FLAGS}")
+      "${VTK_EXTRA_SHARED_LINKER_FLAGS} -Wl,-lc ${CMAKE_SHARED_LINKER_FLAGS}")
     set(CMAKE_MODULE_LINKER_FLAGS
-      "${VTK_EXTRA_SHARED_LINKER_FLAGS} -Wl,--no-undefined -lc ${CMAKE_SHARED_LINKER_FLAGS}")
+      "${VTK_EXTRA_SHARED_LINKER_FLAGS} -Wl,-lc ${CMAKE_SHARED_LINKER_FLAGS}")
     set (CMAKE_EXE_LINKER_FLAGS
-      "${VTK_EXTRA_SHARED_LINKER_FLAGS} -Wl,--no-undefined -lc ${CMAKE_SHARED_LINKER_FLAGS}")
+      "${VTK_EXTRA_SHARED_LINKER_FLAGS} -Wl,-lc ${CMAKE_SHARED_LINKER_FLAGS}")
   endif()
 
   # Set up the debug CXX_FLAGS for extra warnings