libgcompat: Add and use a macro for defining symbol aliases

* Prefer providing the underscore-prefixed symbol as the strong
  definition.
* Do not use a weak alias if the alias is also underscore-prefixed.
* Make libgcompat objects depend on the new header.

[NOTE: I originally took the weak_alias macro from musl's libc.h, but
       it's trivial and the same pattern already in use. If desired, I
       can add the musl copyright notice.]

Signed-off-by: Samuel Holland <samuel@sholland.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/libgcompat/string.c b/libgcompat/string.c
index 60f61fc..7ca0bf6 100644
--- a/libgcompat/string.c
+++ b/libgcompat/string.c
@@ -2,6 +2,8 @@
 #include <stdlib.h> /* strto[u?]ll */
 #include <string.h> /* memcpy, strcpy, strncat, strndup */
 
+#include "alias.h" /* weak_alias */
+
 /* "Checked" memcpy */
 void *__memcpy_chk(void *dest, const void *src, size_t len, size_t destlen)
 {
@@ -60,7 +62,7 @@ char *__strndup(const char *str, size_t count)
 
 /* The existance of this method, and the fact it is used in real code, gives
  * me nightmares. */
-void *rawmemchr(const void *s, int c)
+void *__rawmemchr(const void *s, int c)
 {
 	const unsigned char *haystack = s;
 	unsigned char needle = (unsigned char) c;
@@ -68,9 +70,7 @@ void *rawmemchr(const void *s, int c)
 		;
 	return (void *) haystack;
 }
-
-extern __typeof(rawmemchr) __rawmemchr
-    __attribute__((weak, alias("rawmemchr")));
+weak_alias(__rawmemchr, rawmemchr);
 
 /* Another useless __ alias */
 char *__strtok_r(char *str, const char *delim, char **saveptr)