Valgrind reports definite leaks in minimal compiler runs

[kust1011]

Summary

Running shecc under Valgrind reports reproducible definite leaks in the compiler driver, even for a minimal input program.

This appears to come from:

• heap-allocated token_stream_t objects in gen_file_token_stream() / gen_libc_token_stream()
• heap-allocated predefined macro_t objects in preprocess()
• cached source buffers stored in SRC_FILE_MAP whose values are not released before freeing the hashmap

Reproduction

Minimal input:

int main(void)
{
    return 0;
}

Command:

cat > /tmp/shecc-minimal.c <<'EOF'
int main(void)
{
    return 0;
}
EOF

valgrind \
  --tool=memcheck \
  --leak-check=full \
  --show-leak-kinds=all \
  --track-origins=yes \
  ./out/shecc --no-libc -o /tmp/minimal.elf /tmp/shecc-minimal.c

The same issue is also reproducible without --no-libc, but --no-libc shows that the leak is not caused by <stdio.h> or other libc usage.

Observed result

Valgrind reports:

• definitely lost: 512 bytes in 6 blocks
• indirectly lost: 34 bytes in 1 blocks

Expected result

definitely lost and indirectly lost should both be 0 for this minimal run.