[deimos]

Could the example be extended to include an assembly source file as well as C? I've changed to the makefile to do this myself, but I'm not comfortable with makefiles / gnu make and don't know how to work around the a.mingw.s file that keeps appearing and wanting to be assembled.

# to generate assembler sources: -Wa,-ahl=$@.s

forward-to-backward = $(subst /,\,$1)

subdirs := $(wildcard */)
VPATH = $(subdirs)
csources := $(wildcard *.c) $(wildcard $(addsuffix *.c,$(subdirs)))
asmsources := $(wildcard *.s) $(wildcard $(addsuffix *.s,$(subdirs)))
cobjects := $(addprefix obj8mingw/,$(patsubst %.c,%.o,$(notdir $(csources))))
asmobjects := $(addprefix obj8mingw/,$(patsubst %.s,%.o,$(notdir $(asmsources))))
objects := $(cobjects) $(asmobjects)

# https://stackoverflow.com/questions/4036191/sources-from-subdirectories-in-makefile/4038459
# http://www.microhowto.info/howto/automatically_generate_makefile_dependencies.html

OUT = a.mingw
CC = m68k-amiga-elf-gcc

CCFLAGS = -g -MP -MMD -m68000 -Ofast -nostdlib -Wall -Wno-pointer-sign -Wno-unused-function -Wno-volatile-register-var -Wno-discarded-qualifiers -fomit-frame-pointer -fno-tree-loop-distribution -flto -fwhole-program
ASFLAGS = -Wa,-g,--register-prefix-optional
LDFLAGS = -Wl,--emit-relocs,-Ttext=0,-Map=$(OUT).map

all: $(OUT).exe

$(OUT).exe: $(OUT).elf
	$(info Elf2Hunk $(OUT).exe)
	@elf2hunk $(OUT).elf $(OUT).exe

$(OUT).elf: $(objects)
	$(info Linking a.mingw.elf)
	@$(CC) $(CCFLAGS) $(LDFLAGS) $(objects) -o $@
	@m68k-amiga-elf-objdump --disassemble -S $@ >$(OUT).s 

clean:
	$(info Cleaning...)
	@del /q obj8mingw $(OUT).* 2>nul || rmdir obj8mingw 2>nul || ver>nul

-include $(objects:.o=.d)

$(cobjects) : obj8mingw/%.o : %.c
	@if not exist "$(call forward-to-backward,$(dir $@))" mkdir $(call forward-to-backward,$(dir $@))
	$(info Compiling $<)
	@$(CC) $(CCFLAGS) -c -o $@ $(CURDIR)/$<

$(asmobjects) : obj8mingw/%.o : %.s
	@if not exist "$(call forward-to-backward,$(dir $@))" mkdir $(call forward-to-backward,$(dir $@))
	$(info Assembling $<)
	@$(CC) $(CCFLAGS) $(ASFLAGS) -xassembler-with-cpp -c -o $@ $(CURDIR)/$<

And could clean be added to tasks.json?

{
    // See https://go.microsoft.com/fwlink/?LinkId=733558
    // for the documentation about the tasks.json format
    "version": "2.0.0",
    "tasks": [
        {
            "label": "compile",
            "type": "shell",
            "command": "${command:amiga.bin-path}\\gnumake.exe",
            "args": [
                "-f", "Makefile8mingw", "-j4",
            ],
            "options": {
                "cwd": "${workspaceRoot}",
                "env": {
                    "PATH": "${command:amiga.bin-path}\\opt\\bin;${command:amiga.bin-path}"
                }
            },
            "problemMatcher": [
                {
                    "base": "$gcc",
                    "fileLocation": "absolute"
                }
            ],
            "presentation": {
                "echo": true,
                "reveal": "silent",
                "focus": false,
                "panel": "shared",
                "showReuseMessage": false,
                "clear": true
            },
            "group": {
                "kind": "build",
                "isDefault": true
            }
        },
        {
            "label": "clean",
            "type": "shell",
            "command": "${command:amiga.bin-path}\\gnumake.exe",
            "args": [
                "-f", "Makefile8mingw", "-j4", "clean"
            ],
            "options": {
                "cwd": "${workspaceRoot}",
                "env": {
                    "PATH": "${command:amiga.bin-path}\\opt\\bin;${command:amiga.bin-path}"
                }
            },
            "problemMatcher": [
                {
                    "base": "$gcc",
                    "fileLocation": "absolute"
                }
            ],
            "presentation": {
                "echo": true,
                "reveal": "silent",
                "focus": false,
                "panel": "shared",
                "showReuseMessage": false,
                "clear": true
            },
            "build"
        }
    ]
}

Also, could the --register-prefix-optional option allow most of the first 28 lines of gcc8_a_support.s to be removed, or is there more to it than that?