Unable to compile a build after #19106

[novemberist]

Godot version:

Godot 3.1 master

OS/device including version:
Arch Linux, Kernel 4.17.14, clang 6.0.1, pulseaudio 12.2

Issue description:

Since #19106 was merged, I can not compile Godot 3.1 master branch anymore and get the following error message during the build process:

[Initial build] Compiling ==> drivers/gles3/rasterizer_storage_gles3.cpp
Ranlib Library         ==> modules/libmodules.x11.opt.tools.64.llvm.a
drivers/pulseaudio/audio_driver_pulseaudio.cpp:376:43: error: arithmetic on a pointer to void
                                ret = pa_stream_write(ad->pa_str, ptr + write_ofs, bytes_to_write, NULL, 0LL, PA_SEEK_RELATIVE);
                                                                  ~~~ ^
1 error generated.
[Initial build] scons: *** [drivers/pulseaudio/audio_driver_pulseaudio.x11.opt.tools.64.llvm.o] Error 1
Compiling ==> drivers/gles3/shader_compiler_gles3.cpp
scons: building terminated because of errors.