libgomp.a is a PIC-capable GNU OpenMP runtime for Sesum's portable Linux
x86_64 GCC 8 builds.  Stock Ubuntu x86_64 libgomp.a uses non-PIC TLS
relocations and cannot be embedded in libsr.so.

Source package:
  gcc-8-source_8.4.0-1ubuntu1~18.04_all.deb
  SHA256 245efd0e9bf9ba3868dc6449b4000a8722abe2cea1eba8f2ae0f46e6303a1810

Inner source archive (Ubuntu's Linux/libgomp-relevant patches were then
applied to the extracted tree):
  gcc-8.4.0.tar.xz
  SHA256 e30a6e52d10e1f27ed55104ad233c30bd1e99cfb5ff98ab022dc941edd1b2dd4

Configure command:
  env CC=gcc-8 CXX=g++-8 \
    CFLAGS="-O2 -fPIC -ftls-model=global-dynamic" \
    CXXFLAGS="-O2 -fPIC -ftls-model=global-dynamic" \
    ../src/libgomp/configure \
      --disable-shared --enable-static --with-pic --disable-multilib

Build command:
  make -j4

Result:
  libgomp.a
  SHA256 e2ebfaf455db1a7eb972926240e1f0762b64806e41367dd5ed758e0881ed0da0

The final global-dynamic TLS flag intentionally follows and overrides
libgomp's initial-exec default.  This keeps late ctypes/dlopen loading safe in
an already multi-threaded Python process.  GNU libgomp is distributed under
GPLv3 with the GCC Runtime Library Exception.
