riscv32: the C preprocessor lacks the GCC type predefines newlib needs

• Type: bug (C preprocessor predefines per target) — Track A.
• Filed: 2026-10-05 from ~/museum_landkaart, the ESP-IDF header-import census.

Repro

T=~/.espressif/tools/riscv32-esp-elf/esp-15.2.0_20251204/riscv32-esp-elf
SYS="-I$T/lib/gcc/riscv32-esp-elf/15.2.0/include -I$T/lib/gcc/riscv32-esp-elf/15.2.0/include-fixed -I$T/riscv32-esp-elf/include"
printf '#include <stdint.h>\nint main(void){return 0;}\n' > s.c
pascal26 --target=riscv32 --platform=esp --dump-cpp $SYS s.c | head -1
# error: #error in .../riscv32-esp-elf/include/sys/_intsup.h: "Unable to determine type definition of intptr_t"

echo | riscv32-esp-elf-gcc -march=rv32imc_zicsr_zifencei -mabi=ilp32 -dM -E - > gcc_predefs.h   # 351 lines
printf '#include "gcc_predefs.h"\n#include <stdint.h>\nint main(void){return 0;}\n' > s2.c
pascal26 --target=riscv32 --platform=esp --dump-cpp $SYS s2.c | head -1      # preprocesses fine

(The esp_wifi.h chain's first stdint.h resolves elsewhere and passes. Newlib's stdint.h, inttypes.h and sys/_intsup.h fail as soon as they're reached directly, and IDF reaches them, for example via esp_rom_sys.h.)

Expected

For each target, predefine what GCC predefines for that ABI, at least the __*_TYPE__, __*_MAX__, __SIZEOF_*__, __CHAR_BIT__, __riscv*, __ILP32__ families. The gcc dump above is the oracle. Then a Pascal uses of a header behaves the same, with no prefix file. That matters because a uses has no way to add one.

Acceptance

s.c preprocesses with no prefix; the same for --target=xtensa against xtensa-esp-elf-gcc's own dump.