megaco: Remove VxWorks
Merge branch 'maint'
Merge branch 'maint'

Conflicts:
	lib/diameter/autoconf/vxworks/sed.general
	xcomp/README.md
Fix use of asn1 in megaco
Update megaco documentation
Replace use of driver_send_term() with erl_drv_send_term()
Prepare OTP files for Unicode as default encoding
If GCC is used, treat -Wreturn-type as error
Fix LM_TRY_ENABLE_CFLAG to use correct environment

LM_TRY_ENABLE_CFLAG takes which environment variable should be updated
but only CFLAGS was updated. Though CFLAGS is the normally the intended
variable, others may be used. For instance CXXFLAGS.
Implement ./otp_build configure --enable-silent-rules

With silent rules, the output of make is less verbose and compilation
warnings are easier to spot. Silent rules are disabled by default and
can be disabled or enabled at will by make V=0 and make V=1.
Remove what remains of the Mnemosyne code
Merge branch 'nox/enable-silent-rules/OTP-10726'

* nox/enable-silent-rules/OTP-10726:
  Implement ./otp_build configure --enable-silent-rules
Merge branch 'lh/forget-mnemosyne/OTP-10729'

* lh/forget-mnemosyne/OTP-10729:
  Remove what remains of the Mnemosyne code
  Remove support for the query keyword and query expressions
Merge branch 'rickard/r16/port-optimizations/OTP-10336'

* rickard/r16/port-optimizations/OTP-10336:
  Bump reductions also for immediate driver calls
  Add 'port_count' and 'port_limit' to system_info/1 spec
  Fix documentation
  Replace use of deprecated functions in test cases
  Replace use of driver_send_term() with erl_drv_send_term()

Conflicts:
	erts/preloaded/ebin/erlang.beam
Update copyright years
Prepare release
Update copyright years
Preliminary test case updates
Add rule for test beam'es
Test case cleanup