- Copy stable/10@296371 to releng/10.3 in preparation for 10.3-RC1
builds.
- Update newvers.sh to reflect RC1.
- Update __FreeBSD_version to reflect 10.3.
- Update default pkg(8) configuration to use the quarterly branch.

Approved by: re (implicit)

MFC r281169, r293724, r293796, r294029, r294041, r294058

MFC r281169 (by andrew):
Make global variabled only used in this file static

MFC r294058:
Make common boot file_loadraw name parameter const

MFC r294041:
Remove unused reg param from fdt_fixup_memory

MFC r293724:
Enable warnings in EFI boot code

MFC r293796:
Fix typo in libefi.c

MFC r294029:
Only build EFI components on supported compilers

Sponsored by: Multiplay

MFC r272105: Remove duplicated header content

Approved by: re (gjb, kib)

MFC r271762: Switch to text mode in UEFI boot

The loader previously failed to display on MacBooks and other
systems where the UEFI firmware remained in graphics mode.

Submitted by: Rafael Espindola

Approved by: re

Switch to text mode in UEFI boot

The loader previously failed to display on MacBooks and other systems
where the UEFI firmware remained in graphics mode.

Submitted by: Rafael Espíndola