This is xnu-8019. See this file in:
# -*- mode: makefile;-*-
#
# Copyright (C) 2020 Apple Inc. All rights reserved.
#
# MakeInc.color defines macros used to enable
# colored output of the build log.
#

define _setup_build_log_colors
ifeq ($${XNU_LOGCOLORS},y)
    LOGCOLORS ?= y
endif
ifeq ($$(LOGCOLORS),y)
    # Get a nice list of device code names associated with the build platform
    ifndef CDevs
        #ifdef EMBEDDED_DEVICE_MAP
        #    export CDevs := $$(shell $$(EMBEDDED_DEVICE_MAP) -db $$(EDM_DBPATH) -query "SELECT DISTINCT TargetType FROM Targets WHERE KernelPlatform = '$$(CURRENT_MACHINE_CONFIG_LC)'" | tr '[\r\n]' ':' | sed 's,:$$$$,,')
        #endif
    endif
    ifndef MACHINE_PFX
        export _MACHINE := $$(CURRENT_MACHINE_CONFIG_LC)
        ifeq ($$(CURRENT_MACHINE_CONFIG),NONE)
            export _MACHINE := $$(subst OSX,,$$(PLATFORM))
        endif
        export MACHINE_PFX := $$(shell __A="$$(CURRENT_ARCH_CONFIG_LC)"; \
                                         __As=$$$$((6-$$$${\#__A})); \
                                         printf "%-.6s%*.*s %9.9s" \
                                                "$$$${__A}" \
                                                $$$${__As} $$$${__As} " " \
                                                "$$(_MACHINE)")
    endif
    override LOG_PFX_LEN := 30
    override LOG_PFX_LEN_ADJ := $$(shell __TMP="$$(MACHINE_PFX)"; \
            printf "%d" $$$$(($$(LOG_PFX_LEN) - $$$${\#__TMP} - 3)))
    MACHINE_PFX_COL = $$(shell printf "\\033[1m%s\\033[m" "$$(MACHINE_PFX)")
    # Turn off colored output
    Color0:=$$(shell printf "\\033[m")
    # Start a host command: bold text
    ColorH:=$$(shell printf "\\033[1m")
    # Start a compilation-related command: blue text
    ColorC:=$$(shell printf "[$$(MACHINE_PFX_COL)] \\033[1;34m")
    # Start a MIG command: green text
    ColorM:=$$(shell printf "[$$(MACHINE_PFX_COL)] \\033[1;32m")
    # Start a linking command: purple text
    ColorL:=$$(shell printf "[$$(MACHINE_PFX_COL)] \\033[1;35m")
    # Start a filename
    ColorF:=$$(shell printf "")
    # Start a linked file name: italic text
    ColorLF:=$$(shell printf "\\033[3m")
    # Error strings: red text
    ColorErr:=$$(shell printf "\033[31m")
endif
endef

# vim: set ft=make: