Snowflake breaks the 7.0a3 build

Building Snowflake breaks our 7.0a3 build with the following error:

+ mkdir -p /home/debian/go/src/github.com/keroserene/
+ ln -sf /home/debian/build/go-webrtc /home/debian/go/src/github.com/keroserene/go-webrtc
+ CGO_CXXFLAGS='-D_GLIBCXX_USE_CXX11_ABI=1 -D__STDC_FORMAT_MACROS=1'
+ CGO_LDFLAGS=-latomic
+ go install github.com/keroserene/go-webrtc
# github.com/keroserene/go-webrtc
<command-line>:0:0: warning: "_GLIBCXX_USE_CXX11_ABI" redefined
<command-line>:0:0: note: this is the location of the previous definition
# github.com/keroserene/go-webrtc
<command-line>:0:0: warning: "_GLIBCXX_USE_CXX11_ABI" redefined
<command-line>:0:0: note: this is the location of the previous definition
# github.com/keroserene/go-webrtc
<command-line>:0:0: warning: "_GLIBCXX_USE_CXX11_ABI" redefined
<command-line>:0:0: note: this is the location of the previous definition
# github.com/keroserene/go-webrtc
/home/debian/install/binutils/bin/ld.gold.real: error: ../../go/src/github.com/keroserene/go-webrtc/lib/libwebrtc-linux-386-magic.a(dump_syms_regtest.o): unsupported ELF file type 2
collect2: error: ld returned 1 exit status

I double-checked that the commits I am on are the same as in the patch for legacy/trac#21748 (moved). Furthermore, I made a make clean-webrtc and the build started with tbb-7.0a3-build3.

There are actually two issues here:

We need to unblock the 7.0a3 build as soon as possible as we want to release the first ESR52-based Tor Browser alpha next week.
I'd like to understand how this can happen at all given that we did not change the commits compared to the fix in legacy/trac#21748 (moved) and I tested that the building worked back then. I somehow doubt that arlolra and I made the same mistake (by using the wrong commit or something).

I need to have a fix for that within the next 24 hours, otherwise do I need to disable Snowflake in the alphas.