Bundled zlib is compiled despite the --shared-zlib configure-flag

[UnitedMarsupials-zz]

All operating systems out there -- except, perhaps, Windows -- already include libz. However, when building node with the --shared-zlib flag, the bundled version of the library is compiled anyway -- even if the node-executable duly uses the OS-provded library (/lib/libz.so.6 in my case).

This is both wasteful and dangerous, because some day it may happen, that a bundled header-file will be #include-ed, that will somehow disagree with the implementation provided by the OS. It should be possible to build node with deps/zlib completely absent -- for safety.

Other bundled libraries (cares, uv) do not seem to be mishandled this way -- only zlib.

[bnoordhuis]

The bundled zlib is used by the C++ test suite, that is why. The fix is probably this:

diff --git a/node.gyp b/node.gyp
index abba4c3..5075c51 100644
--- a/node.gyp
+++ b/node.gyp
@@ -895,29 +895,33 @@
       ],
 
       'conditions': [
         ['v8_inspector=="true"', {
           'defines': [
             'HAVE_INSPECTOR=1',
           ],
           'dependencies': [
-            'deps/zlib/zlib.gyp:zlib',
             'v8_inspector_compress_protocol_json#host'
           ],
           'include_dirs': [
             '<(SHARED_INTERMEDIATE_DIR)'
           ],
           'sources': [
             'src/inspector_socket.cc',
             'src/inspector_socket_server.cc',
             'test/cctest/test_inspector_socket.cc',
             'test/cctest/test_inspector_socket_server.cc'
           ],
           'conditions': [
+            [ 'node_shared_zlib=="false"', {
+              'dependencies': [
+                'deps/zlib/zlib.gyp:zlib',
+              ]
+            }],
             [ 'node_shared_openssl=="false"', {
               'dependencies': [
                 'deps/openssl/openssl.gyp:openssl'
               ]
             }],
             [ 'node_shared_http_parser=="false"', {
               'dependencies': [
                 'deps/http_parser/http_parser.gyp:http_parser'

Contributors, feel free to steal. I'm not going to PR it, I'm on holiday!

[gibfahn]

Will test/steal ^