Fix pread/pwrite for LP64.

Unlike on 32-bit systems where off_t is 32-bit, we don't want to
throw away the top 32 bits of an LP64 system's 64-bit off_t.

Change-Id: Ib2e0daeb4fc0b8ab3d1b983d0b371d8f81033b50
diff --git a/libc/arch-x86_64/syscalls/pread64.S b/libc/arch-x86_64/syscalls/pread64.S
index 25378c8..05dc021 100644
--- a/libc/arch-x86_64/syscalls/pread64.S
+++ b/libc/arch-x86_64/syscalls/pread64.S
@@ -17,3 +17,6 @@
 1:
     ret
 END(pread64)
+
+    .globl _C_LABEL(pread)
+    .equ _C_LABEL(pread), _C_LABEL(pread64)
diff --git a/libc/arch-x86_64/syscalls/pwrite64.S b/libc/arch-x86_64/syscalls/pwrite64.S
index c3692e9..a1e0ea1 100644
--- a/libc/arch-x86_64/syscalls/pwrite64.S
+++ b/libc/arch-x86_64/syscalls/pwrite64.S
@@ -17,3 +17,6 @@
 1:
     ret
 END(pwrite64)
+
+    .globl _C_LABEL(pwrite)
+    .equ _C_LABEL(pwrite), _C_LABEL(pwrite64)