MFC r316513 (by jhb):

Sync SYSTEM_LD in Makefile.arm with kern.pre.mk.

• Add --no-warn-mismatch.
• Use same whitespace to make future updates simpler.

Reviewed by: imp (part of a larger change)
Sponsored by: DARPA / AFRL
Differential Revision: https://reviews.freebsd.org/D10085

MFC r316514 (by jhb):

Always pass the linker emulation via -m when linking modules and kernels.

Previously the linker emulation was only passed when building binary
objects for firmware modules. This change always passes the desired
output format for kernel modules and kernels rather than requiring the
toolchain's default output format to match the desired output format.
This in turn permits use of external toolchains whose default output
format does not match the desired output format.

Reviewed by: imp, emaste
Sponsored by: DARPA / AFRL
Differential Revision: https://reviews.freebsd.org/D10085

MFC r320179 (by emaste):

add -znotext to kernel module link invocation

ARM kernel modules require .text relocations (DT_TEXTREL) in shared
object ouptut, which is not allowed by default by lld. Add the -znotext
option to enable this. For simplicity add it unconditionally: it is
already default and thus either redundant (GNU BFD ld and gold from
ports) or ignored as an unknown option (GNU BFD ld 2.17.50 in the base
system).

Reviewed by: kib
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D11250