[ORC][MachO] Allow multiple LC_BUILD_VERSION commands.

No testcase: I'm still thinking about the best way to test this.

Author: lhames

llvm/include/llvm/ExecutionEngine/Orc/MachOPlatform.h

@@ -73,13 +73,12 @@ class MachOPlatform : public Platform {
     /// will be used.
     std::optional<Dylib> IDDylib;
 
-    /// Override for LC_BUILD_VERSION. If this is nullopt then
-    std::optional<BuildVersionOpts> BuildVersion;
-
     /// List of LC_LOAD_DYLIBs.
     std::vector<Dylib> LoadDylibs;
     /// List of LC_RPATHs.
     std::vector<std::string> RPaths;
+    /// List of LC_BUILD_VERSIONs.
+    std::vector<BuildVersionOpts> BuildVersion;
 
     HeaderOptions() = default;
     HeaderOptions(Dylib D) : IDDylib(std::move(D)) {}

llvm/lib/ExecutionEngine/Orc/MachOPlatform.cpp

@@ -1725,11 +1725,9 @@ jitlink::Block &createHeaderBlock(MachOPlatform &MOP,
   else
     B.template addLoadCommand<MachO::LC_ID_DYLIB>(JD.getName(), 0, 0, 0);
 
-  if (Opts.BuildVersion)
+  for (auto &BV : Opts.BuildVersion)
     B.template addLoadCommand<MachO::LC_BUILD_VERSION>(
-        Opts.BuildVersion->Platform, Opts.BuildVersion->MinOS,
-        Opts.BuildVersion->SDK, static_cast<uint32_t>(0));
-
+        BV.Platform, BV.MinOS, BV.SDK, static_cast<uint32_t>(0));
   for (auto &D : Opts.LoadDylibs)
     B.template addLoadCommand<MachO::LC_LOAD_DYLIB>(
         D.Name, D.Timestamp, D.CurrentVersion, D.CompatibilityVersion);