Make sure fPIC gets propagated to nvcc in all cases.

dlib/CMakeLists.txt

@@ -529,6 +529,11 @@ if (NOT TARGET dlib)
             # magic in the standard C++ header files (since nvcc uses gcc headers on
             # linux).
             list(APPEND CUDA_NVCC_FLAGS "-arch=sm_30;-std=c++11;-D__STRICT_ANSI__;-D_MWAITXINTRIN_H_INCLUDED;-D_FORCE_INLINES;${FLAGS_FOR_NVCC}")
+            if (CMAKE_POSITION_INDEPENDENT_CODE)
+               # sometimes this setting isn't propagated to NVCC, which then causes the
+               # compile to fail.  So make sure it's propagated.
+               list(APPEND CUDA_NVCC_FLAGS "-Xcompiler -fPIC")
+            endif()
 
             include(cmake_utils/test_for_cudnn/find_cudnn.txt)
 

dlib/cmake_utils/add_python_module

@@ -132,6 +132,7 @@ if (CMAKE_COMPILER_IS_GNUCXX)
     # -fPIC for GCC but sometimes it still doesn't get set, so make sure it
     # does.
     add_definitions("-fPIC")
+    set(CMAKE_POSITION_INDEPENDENT_CODE True)
 else()
     set(CMAKE_POSITION_INDEPENDENT_CODE True)
 endif()