Add GNU-compatible strerror_r.
We already had the POSIX strerror_r, but some third-party code defines
_GNU_SOURCE and expects to get the GNU strerror_r instead.
This exposed a bug in the libc internal logging functions where unlike
their standard brethren they wouldn't return the number of bytes they'd
have liked to have written.
Bug: 16243479
Change-Id: I1745752ccbdc569646d34f5071f6df2be066d5f4
diff --git a/libc/include/string.h b/libc/include/string.h
index 0a1d653..b0643af 100644
--- a/libc/include/string.h
+++ b/libc/include/string.h
@@ -67,8 +67,12 @@
extern char* strtok(char* __restrict, const char* __restrict);
extern char* strtok_r(char* __restrict, const char* __restrict, char** __restrict);
-extern char* strerror(int);
-extern int strerror_r(int errnum, char *buf, size_t n);
+extern char* strerror(int);
+#if defined(__USE_GNU)
+extern char* strerror_r(int, char*, size_t) __RENAME(__gnu_strerror_r);
+#else /* POSIX */
+extern int strerror_r(int, char*, size_t);
+#endif
extern size_t strnlen(const char *, size_t) __purefunc;
extern char* strncat(char* __restrict, const char* __restrict, size_t);