From 4a0bb736c9de1ffd6fc845fa30021c524ef163a1 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers3@gmail.com>
Date: Fri, 20 Nov 2020 15:03:11 -0800
Subject: [PATCH] lib: make freestanding memset() et al. symbols "weak"

This allows these symbols to be overridden by another definition of
these symbols somewhere else in the binary.

Resolves https://github.com/ebiggers/libdeflate/issues/107
---
 lib/utils.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/lib/utils.c b/lib/utils.c
index a076d82..c626af1 100644
--- a/lib/utils.c
+++ b/lib/utils.c
@@ -85,7 +85,8 @@ libdeflate_set_memory_allocator(void *(*malloc_func)(size_t),
  */
 #ifdef FREESTANDING
 #undef memset
-void *memset(void *s, int c, size_t n)
+void * __attribute__((weak))
+memset(void *s, int c, size_t n)
 {
 	u8 *p = s;
 	size_t i;
@@ -96,7 +97,8 @@ void *memset(void *s, int c, size_t n)
 }
 
 #undef memcpy
-void *memcpy(void *dest, const void *src, size_t n)
+void * __attribute__((weak))
+memcpy(void *dest, const void *src, size_t n)
 {
 	u8 *d = dest;
 	const u8 *s = src;
@@ -108,7 +110,8 @@ void *memcpy(void *dest, const void *src, size_t n)
 }
 
 #undef memmove
-void *memmove(void *dest, const void *src, size_t n)
+void * __attribute__((weak))
+memmove(void *dest, const void *src, size_t n)
 {
 	u8 *d = dest;
 	const u8 *s = src;
@@ -123,7 +126,8 @@ void *memmove(void *dest, const void *src, size_t n)
 }
 
 #undef memcmp
-int memcmp(const void *s1, const void *s2, size_t n)
+int __attribute__((weak))
+memcmp(const void *s1, const void *s2, size_t n)
 {
 	const u8 *p1 = s1;
 	const u8 *p2 = s2;