build: fix rpcgen problem on FreeBSD

rpcgen on FreeBSD and on Linux store the generated files in different
directories, either where the source file is stored or into the current
directory.

We now check both options to copy the generated files when being built
outside of the source tree.

core/src/ndmp/CMakeLists.txt

@@ -93,7 +93,8 @@ foreach(NDMP_VERSION 0 1 2 3 4 9)
          PRE_BUILD
          OUTPUT ndmp${NDMP_VERSION}.h ndmp${NDMP_VERSION}_xdr.c
          COMMAND  ${RPCGEN} ${RPCGEN_PARAMS} ${CMAKE_CURRENT_SOURCE_DIR}/ndmp${NDMP_VERSION}.x
-         COMMAND cp ${CMAKE_CURRENT_SOURCE_DIR}/ndmp${NDMP_VERSION}.h ${CMAKE_CURRENT_SOURCE_DIR}/ndmp${NDMP_VERSION}_xdr.c  ${CMAKE_CURRENT_BINARY_DIR}
+         COMMAND cp ndmp${NDMP_VERSION}.h ndmp${NDMP_VERSION}_xdr.c ${CMAKE_CURRENT_SOURCE_DIR}
+              || cp ${CMAKE_CURRENT_SOURCE_DIR}/ndmp${NDMP_VERSION}.h ${CMAKE_CURRENT_SOURCE_DIR}/ndmp${NDMP_VERSION}_xdr.c  ${CMAKE_CURRENT_BINARY_DIR}
          DEPENDS ${RPCGEN} ${CMAKE_CURRENT_SOURCE_DIR}/ndmp${NDMP_VERSION}.x
          )
    ENDIF()