bail out of activation if environment is not writable

Reinstate 7c0287a

Closes #1126

recipe/activate.sh

@@ -23,6 +23,12 @@ _la_log "Beginning libarrow activation."
 # where the GDB wrappers get installed
 _la_gdb_prefix="$CONDA_PREFIX/share/gdb/auto-load"
 
+# If the directory is not writable, nothing can be done
+if [ ! -w "$_la_gdb_prefix" ]; then
+    _la_log 'No rights to modify $_la_gdb_prefix, cannot create symlink'
+    return
+fi
+
 # this needs to be in sync with ARROW_GDB_INSTALL_DIR in build.sh
 _la_placeholder="replace_this_section_with_absolute_slashed_path_to_CONDA_PREFIX"
 # the paths here are intentionally stacked, see #935, resp.

recipe/meta.yaml

@@ -21,7 +21,7 @@ source:
     folder: testing
 
 build:
-  number: 6
+  number: 7
   # for cuda support, building with one version is enough to be compatible with
   # all later versions, since arrow is only using libcuda, and not libcudart.
   skip: true  # [cuda_compiler_version not in ("None", cuda_compiler_version_min)]