gnu: glibc: Update to 2.29.

gnu: glibc: Update to 2.29.

* gnu/packages/patches/glibc-bootstrap-system.patch,
gnu/packages/patches/glibc-supported-locales.patch: Adjust for glibc 2.29.
* gnu/packages/patches/glibc-2.28-supported-locales.patch,
gnu/packages/patches/glibc-CVE-2019-7309.patch,
gnu/packages/patches/glibc-CVE-2019-9169.patch,
gnu/packages/patches/glibc-2.29-git-updates.patch: New files.
* gnu/local.mk (dist_patch_DATA): Adjust accordingly.
* gnu/packages/base.scm (glibc): Update to 2.29.
[source](patches): Add 'glibc-CVE-2019-7309.patch',
'glibc-CVE-2019-9169.patch', and 'glibc-2.29-git-updates.patch'.  Remove
'glibc-hurd-magic-pid.patch'.
[native-inputs]: Add PYTHON-MINIMAL.
(glibc-2.28): New public variable.
* gnu/packages/commencement.scm (expat-sans-tests, python-boot0): New variables.
(glibc-final-with-bootstrap-bash)[native-inputs]: Add PYTHON-BOOT0.
* gnu/packages/python.scm (python-3.7)[arguments]: Disable test that fails
with glibc 2.29.