[tor-bugs] #28205 [Obfuscation/Snowflake]: linking against other libwebrtc binaries errors out on missing symbols

[Tor Bug Tracker & Wiki]

#28205: linking against other libwebrtc binaries errors out on missing symbols
-----------------------------------+---------------------------
 Reporter:  eighthave              |          Owner:  eighthave
     Type:  defect                 |         Status:  accepted
 Priority:  Medium                 |      Milestone:
Component:  Obfuscation/Snowflake  |        Version:
 Severity:  Major                  |     Resolution:
 Keywords:  android                |  Actual Points:
Parent ID:                         |         Points:
 Reviewer:                         |        Sponsor:
-----------------------------------+---------------------------

Comment (by dcf):

 Replying to [comment:10 eighthave]:
 > So I think this is starting to make sense to me.  The Android .pc file
 that I wrote already includes `        -D_GLIBCXX_USE_CXX11_ABI=0`, so I
 guess I should change that to 1 also?  Does this still need to also be set
 in `CGO_CXXFLAGS`?  Should this be building with gcc?  I think gomobile
 defaults to clang.

 If you put `-D_GLIBCXX_USE_CXX_ABI=1` in `CGO_CXXFLAGS`, it will override
 the setting in the .pc file (with a harmless warning about redefinition).

 It's better to leave `-D_GLIBCXX_USE_CXX11_ABI=0` in the .pc file for now,
 because we're currently keeping the pre-built library at that ABI version.
 In the Tor Browser build, though, we're overriding it to `1`.
 Cf. https://github.com/keroserene/go-
 webrtc/commit/a1272c08ab1d5ca154c6794ddc5f73d2e576fe1b.

 I think it should work with either GCC or Clang. I think currently in the
 Tor Browser build, we're using GCC for linux and Clang for mac, at least
 if I'm interpreting [https://gitweb.torproject.org/builders/tor-browser-
 build.git/tree/projects/webrtc/build?id=2b270ede9341f8ce496e811f7af9077e3eed9049#n81
 this] and [https://gitweb.torproject.org/builders/tor-browser-
 build.git/tree/projects/webrtc/build?id=2b270ede9341f8ce496e811f7af9077e3eed9049#n118
 this] correctly.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/28205#comment:12>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online