There is a way to suppress the path translation by setting MSYS_NO_PATHCONV=1
in Windows Git MSys or MSYS2_ARG_CONV_EXCL="*"
in MSYS2.
Alternatively, you can set the variable only temporarily just for that command by putting the assignment just before the command itself:
MSYS_NO_PATHCONV=1 arm-none-linux-gnueabi-gcc.exe -Wall -g \
-Wl,--dynamic-linker=/usr/lib/myrpath/ld-linux.so.3 \
-Wl,-rpath=/usr/lib/myrpath \
-I../targetsysroot/usr/include \
myprogram.c -o myprogram