[compiler-rt] Suppress -Wunused-result due to ::write when _FORTIFY_SOURCE>0 in glibc

Noticed by Peter Foley.
In glibc, ::write is declared as __attribute__((__warn_unused_result__)) when __USE_FORTIFY_LEVEL is larger than 0.

GitOrigin-RevId: 1ef0e94d5b0206f69e4e822c6828d0b5121c11fb
diff --git a/FuzzerIOPosix.cpp b/FuzzerIOPosix.cpp
index 0da063a..4706a40 100644
--- a/FuzzerIOPosix.cpp
+++ b/FuzzerIOPosix.cpp
@@ -159,7 +159,7 @@
 }
 
 void RawPrint(const char *Str) {
-  write(2, Str, strlen(Str));
+  (void)write(2, Str, strlen(Str));
 }
 
 void MkDir(const std::string &Path) {