[llvm] [SystemZ][z/OS] Implement executePostLayoutBinding for GOFFObjectWriter (PR #67868)

[via llvm-commits]

================
@@ -18,10 +18,50 @@
 namespace llvm {
 
 class MCSymbolGOFF : public MCSymbol {
+  Align Alignment;
+  enum SymbolFlags : uint16_t {
+    SF_NoRent = 0x01, // Symbol is no-reentrant.
+    SF_Alias = 0x02,  // Symbol is alias.
+    SF_Hidden = 0x04, // Symbol is hidden, aka not exported.
+    SF_Weak = 0x08,   // Symbol is weak.
+  };
+
+  enum {
+    // Shift value for GOFF::ESDExecutable. 3 possible values. 2 bits.
+    GOFF_Executable_Shift = 6,
+    GOFF_Executable_Bitmask = 0x3,
+  };
----------------
diggerlin wrote:

I prefer constexpr in this case. 
constexpr uint8_t GOFF_Executable_Shift = 6;
constexpr uint8_t  GOFF_Executable_Bitmask =0x03;

https://github.com/llvm/llvm-project/pull/67868