Bump backward compatibility to 5.3

Author: Azoy

stdlib/public/runtime/CompatibilityOverride.cpp

@@ -27,7 +27,7 @@ using namespace swift;
 /// The definition of the contents of the override section.
 ///
 /// The runtime looks in the main executable (not any libraries!) for a
-/// __swift52_hooks section and uses the hooks defined therein. This struct
+/// __swift53_hooks section and uses the hooks defined therein. This struct
 /// defines the layout of that section. These hooks allow extending
 /// runtime functionality when running apps built with a more recent
 /// compiler. If additional hooks are needed, they may be added at the
@@ -52,7 +52,7 @@ static OverrideSection *getOverrideSectionPtr() {
   swift_once(&Predicate, [](void *) {
     size_t Size;
     OverrideSectionPtr = static_cast<OverrideSection *>(
-                             lookupSection("__DATA", "__swift52_hooks", &Size));
+                             lookupSection("__DATA", "__swift53_hooks", &Size));
     if (Size < sizeof(OverrideSection))
       OverrideSectionPtr = nullptr;
   }, nullptr);

unittests/runtime/CompatibilityOverride.cpp

@@ -60,7 +60,7 @@ struct OverrideSection {
 #include "../../stdlib/public/runtime/CompatibilityOverride.def"
 };
 
-OverrideSection Overrides __attribute__((section("__DATA,__swift52_hooks"))) = {
+OverrideSection Overrides __attribute__((section("__DATA,__swift53_hooks"))) = {
   0,
 #define OVERRIDE(name, ret, attrs, ccAttrs, namespace, typedArgs, namedArgs) \
   name ## Override,