Fail to build csources_v3 on Raspberry Pi 5 with 32-bit Raspberry Pi OS

[demotomohiro]

Nim Version

Nim Compiler Version 2.3.1 [Linux: arm]
Compiled at 2025-11-18
Copyright (c) 2006-2025 by Andreas Rumpf

git hash: 46d4079
active boot switches: -d:release

Description

Compiling csources_v3 on Raspberry Pi 5 with Raspberry Pi OS 32-bit fails.
You might get the same error on Raspberry Pi 3, 4 and zero 2 with Raspberry Pi OS 32-bit because they have 64bit CPU.

Current Output

$ sh build_all.sh
...
cc -Ic_code -w -fmax-errors=3 -fno-strict-aliasing -O3 -fno-ident -fno-math-errno    -c -o c_code/2_18/@psystem@sexceptions.nim.o c_code/2_18
/@psystem@sexceptions.nim.c
In file included from c_code/2_18/@psystem@sexceptions.nim.c:4:
c_code/nimbase.h:273:35: error: static assertion failed: "Pointer size mismatch between Nim and C/C++ backend. You probably need to setup the
 backend compiler for target CPU."
  273 | #define NIM_STATIC_ASSERT(x, msg) _Static_assert((x), msg)
      |                                   ^~~~~~~~~~~~~~
c_code/nimbase.h:562:1: note: in expansion of macro ‘NIM_STATIC_ASSERT’
  562 | NIM_STATIC_ASSERT(sizeof(NI) == sizeof(void*) && NIM_INTBITS == sizeof(NI)*8, "Pointer size mismatch between Nim and C/C++ backend. Y
ou probably need to setup the backend compiler for target CPU.");
      | ^~~~~~~~~~~~~~~~~

Expected Output

Compiles without errors

Known Workarounds

No response

Additional Information

It seems makefile in csources_v3 try to build code for 64bit CPU but gcc target is 32bit CPU.
On Raspberry Pi 5 with 32-bit OS, uname -m command prints aarch64 but gcc -dumpmachine prints arm-linux-gnueabihf.
As makefile in csources_v3 uses uname -m to detect CPU arch, it builds Nim code for 64bit CPU but gcc target is 32bit CPU.

If makefile uses gcc -dumpmachine instead of uname -m to detect CPU arch, it can detect gcc target CPU arch and probably prevents above error.
But parsing output of gcc -dumpmachine seems tricky.
https://wiki.osdev.org/Target_Triplet
https://mcyoung.xyz/2025/04/14/target-triples/
You can get CPU arch from target triplet easily as it is always comes first, but OS part is tricky.