www/qt5-webengine: Update to 5.13.0

[kai]

Summary

• Under the hood runs Chromium 73.0.3683.105 with applied security fixes from Chrome up to version 74.0.3729.157.

• Most of the patches were synced with www/chromium 73.0.3683.103 (= rP498089).

• Added "xorg" to USES as using USE_XORG alone is deprecated.

Notable changes:

• GN keywords 'use_system_{libusb,libcxx}' aren't used anymore thus both were removed from 'freebsd.pri'
• In various GN files the OS is now identified by 'freebsd' (prior it was 'bsd') so 'mkspecs/features/functions.prf' was changed accordingly.
• The hook up of the sandbox feature is no longer excluded which led to some more patches (= patch-*crashpad* files)

Test Plan

The actual progress so far:

'OK' = Builds fine with ALSA/PULSE/SNDIO

+----------------------+-------+--------+----------+----------+
|                      | amd64 | i386   | aarch64  | armv7    |
+----------------------+-------+--------+----------+----------+
| 11.3-RELEASE         | OK    | OK     | N/A [2]  | N/A [2]  |
+----------------------+-------+--------+----------+----------+
| 12.0-RELEASE         | OK    | OK     | OK       | FAIL [3] |
+----------------------+-------+--------+----------+----------+
| 13.0-CURRENT@r353466 | OK    | OK [1] | N/A [2]  | N/A [2]  |
+----------------------+-------+--------+----------+----------+

[1]: Builds with DEBUG fails due exhausted memory when linking (this was already the case with the 5.12 release)
[2]: I'll have to investigate the Tier-2 jails and try then a new build. I expect that there will be no problems regarding aarch64.
[3]: Fails upon invocation of 'mksnapsnot' and emits a coredump of QEMU (Some tweaking is still required)

A question/note from my view:

The following patches have all hardcoded paths of '/usr/local' in it. Those occurences should be IMHO replaced with %%LOCALBASE%% and then replaced with '${LOCALBASE}' in the 'post-patch' stage:

• patch-src_3rdparty_chromium_build_toolchain_gcc__toolchain.gni
• patch-src_3rdparty_chromium_chrome_common_chrome__paths.cc
• patch-src_3rdparty_chromium_third__party_pdfium_core_fxge_fx__ge__linux.cpp
• patch-src_3rdparty_chromium_third__party_pdfium_xfa_fgas_font_cfx__fontsourceenum__file.cpp
• patch-src_3rdparty_gn_build_gen.py

[kai]

Re-added/modified some patches from rP497877 and rP499210 to get a better progress with armv7.

[tcberner]

[kai]

Closing this review that was committed in rP515731.