[libc] fix rv32 mmap in auxv library

[SchrodingerZhu]

Fix auxv rv32 build problem

[llvmbot]

@llvm/pr-subscribers-libc

Author: Schrodinger ZHU Yifan (SchrodingerZhu)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/162519.diff

1 Files Affected:

• (modified) libc/src/__support/OSUtil/linux/auxv.h (+6-1)

diff --git a/libc/src/__support/OSUtil/linux/auxv.h b/libc/src/__support/OSUtil/linux/auxv.h
index 7fb996f01dd84..894868ae5824d 100644
--- a/libc/src/__support/OSUtil/linux/auxv.h
+++ b/libc/src/__support/OSUtil/linux/auxv.h
@@ -81,7 +81,12 @@ LIBC_INLINE void Vector::initialize_unsafe(const Entry *auxv) {
 [[gnu::cold]]
 LIBC_INLINE void Vector::fallback_initialize_unsync() {
   constexpr size_t AUXV_MMAP_SIZE = FALLBACK_AUXV_ENTRIES * sizeof(Entry);
-  long mmap_ret = syscall_impl<long>(SYS_mmap, nullptr, AUXV_MMAP_SIZE,
+#ifdef SYS_mmap2
+  constexpr int MMAP_SYSNO = SYS_mmap2;
+#else
+  constexpr int MMAP_SYSNO = SYS_mmap;
+#endif
+  long mmap_ret = syscall_impl<long>(MMAP_SYSNO, nullptr, AUXV_MMAP_SIZE,
                                      PROT_READ | PROT_WRITE,
                                      MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
   // We do not proceed if mmap fails.