Fix cross-compile issue with newlib on Ubuntu 24.04

[pocke]

This PR fixes a cross-compile issue of PicoRuby.

Problem

I'm trying to build PicoRuby, which uses Prism, on Ubuntu 24.04. But it causes the following build error.

$ rake pico --trace

(snip)

CC    build/repos/r2p2-cortex-m0plus/mruby-compiler2/lib/prism/src/util/pm_integer.c -> build/r2p2-cortex-m0plus/mrbgems/mruby-compiler2/lib/pm_integer.o
/home/pocke/ghq/github.com/picoruby/R2P2/lib/picoruby/build/repos/r2p2-cortex-m0plus/mruby-compiler2/lib/prism/src/util/pm_integer.c: In function 'pm_integer_string':
/home/pocke/ghq/github.com/picoruby/R2P2/lib/picoruby/build/repos/r2p2-cortex-m0plus/mruby-compiler2/lib/prism/src/util/pm_integer.c:623:44: error: expected ')' before 'PRIu64'
  623 |         pm_buffer_append_format(buffer, "%" PRIu64, value);
      |                                ~           ^~~~~~~
      |                                            )
/home/pocke/ghq/github.com/picoruby/R2P2/lib/picoruby/build/repos/r2p2-cortex-m0plus/mruby-compiler2/lib/prism/src/util/pm_integer.c:2:1: note: 'PRIu64' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?
    1 | #include "prism/util/pm_integer.h"
  +++ |+#include <inttypes.h>
    2 | 
/home/pocke/ghq/github.com/picoruby/R2P2/lib/picoruby/build/repos/r2p2-cortex-m0plus/mruby-compiler2/lib/prism/src/util/pm_integer.c:622:24: warning: unused variable 'value' [-Wunused-variable]
  622 |         const uint64_t value = ((uint64_t) integer->values[0]) | ((uint64_t) integer->values[1] << 32);
      |                        ^~~~~
rake aborted!

(snip)

Cause

The Raspberry Pi Pico SDK had the same problem. raspberrypi/pico-examples#520
This issue describes the problem. In short, it looks like a bug of newlib.

Reproduce

I reproduced it on the R2P2 repository, which is a .
https://github.com/picoruby/R2P2

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 24.04.1 LTS
Release:        24.04
Codename:       noble

$ sudo apt install cmake python3 build-essential gcc-arm-none-eabi libnewlib-arm-none-eabi libstdc++-arm-none-eabi-newlib

$ git clone https://github.com/picoruby/R2P2.git
$ cd R2P2
$ rake setup
$ rake pico --trace
# => It shows the error.

BTW, R2P2 requires setting PICO_SDK_PATH environment variable, but it is not necessary for this reproduction because it fails before using PICO_SDK_PATH.

Sorry for the lack of minimum reproduction. I'm not very familiar with PicoRuby and the building system, so I'm not sure how to minimize the reproduction process. 🙇

Solution

Add #include <sys/types.h> before #include <inttypes.h>.
This solution is based on raspberrypi/pico-sdk#1863.

I've confirmed that this patch fixes the error in my environment.

[kddnewton]

I don't know for sure but I'm hoping sys/types.h is on all of the platforms that CRuby supports?