en changeant le path, et en mettant le chemin de msys avant mksnt .. ça marche un peu mieux
mais c pas encore ça
j'obtiens
C:\devkitPro\examples\nds\Graphics\2D\256_color_bmp>make
grit /c/devkitPro/examples/nds/Graphics/2D/256_color_bmp/data/drunkenlogo.png -fts -odrunkenlogo
---grit v0.7.2 ---
** src[ 0] : c:/devkitPro/examples/nds/Graphics/2D/256_color_bmp/data/drunkenlogo.png
Conversion finished.
drunkenlogo.s
arm-eabi-gcc -MMD -MP -MF /c/devkitPro/examples/nds/Graphics/2D/256_color_bmp/build/drunkenlogo.d -x assembler-with-cpp -g -mthumb -mthumb-interwork -c drunkenlogo.s -o drunkenlogo.o
main.cpp
arm-eabi-g++ -MMD -MP -MF /c/devkitPro/examples/nds/Graphics/2D/256_color_bmp/build/main.d -g -Wall -O2 -mcpu=arm9tdmi -mtune=arm9tdmi -fomit-frame-pointer -ffast-math -mthumb -mthumb-interwork -I/c/devkitPro/examples/nds/Graphics/2D/256_color_bmp/include -I/c/devkitpro/libnds/include -I/c/devkitpro/libnds/include -I/c/devkitPro/examples/nds/Graphics/2D/256_color_bmp/build -DARM9 -fno-rtti -fno-exceptions -c /c/devkitPro/examples/nds/Graphics/2D/256_color_bmp/source/main.cpp -o main.o
linking 256_color_bmp.elf
c:/devkitpro/devkitarm/bin/../lib/gcc/arm-eabi/4.1.2/../../../../arm-eabi/lib/thumb/ds_arm9_crt0.o: In function `CIDLoop':
ds_arm9_crt0.s:(.init+0x2ac): undefined reference to `initSystem'
collect2: ld returned 1 exit status
make[1]: *** [/c/devkitPro/examples/nds/Graphics/2D/256_color_bmp/256_color_bmp.elf] Error 1
rm drunkenlogo.s
make: *** [build] Error 2
C:\devkitPro\examples\nds\Graphics\2D\256_color_bmp>
une idée pour initSystem

?