This limitation indeed forces you to disable the default startup files with -nostartfiles
(I prefer -nostdlib
). You then need to build by yourself the list of run-time objects. gcc has the option -print-file-name
to print the absolute path of libraries it was compiled with (crtbegin.o, crtend.o, libgcc.a...). For example: arm-eabi-g++ <FLAGS> -print-file-name=crtbegin.o
Here is the GNU Make macro I use (providing gcc and cflags):
define m.in/toolchain/gnu/locate =
$(strip
$(shell $(m.in/toolchain/gnu/bin/gcc) $(m.in/toolchain/gnu/cflags) \
-print-file-name=$(m.in/argv/1))
)
endef
crtn := $(call m.in/toolchain/gnu/locate, crtn.o)