Enable -D_FORTIFY_SOURCE=3 globally by default.

Bug: b/291762537
Test: mm
Change-Id: Ie6759efc1573c1ae91176687e6b9ea4726a983d8
diff --git a/cc/config/global.go b/cc/config/global.go
index b19682d..61f48c4 100644
--- a/cc/config/global.go
+++ b/cc/config/global.go
@@ -166,7 +166,7 @@
 		"-funwind-tables",
 		"-fstack-protector-strong",
 		"-Wa,--noexecstack",
-		"-D_FORTIFY_SOURCE=2",
+		"-D_FORTIFY_SOURCE=3",
 
 		"-Wstrict-aliasing=2",