Predefine version D_ObjectiveC _before_ printing predefs with -v

This fixes 64bit-macOS-exclusive runnable/test18335.sh.

Author: kinke

dmd/mars.d

@@ -551,7 +551,14 @@ extern (C++) int mars_mainBody(ref Strings files, ref Strings libmodules)
     Objc._init();
     builtin_init();
 
-  version (IN_LLVM) {} else
+  version (IN_LLVM)
+  {
+    // LDC prints binary/version/config before entering this function.
+    // DMD prints the predefined versions as part of addDefaultVersionIdentifiers().
+    // Let's do it here after initialization, as e.g. Objc.init() may add `D_ObjectiveC`.
+    printPredefinedVersions();
+  }
+  else
   {
     printPredefinedVersions();
 
@@ -1610,8 +1617,7 @@ void addDefaultVersionIdentifiers()
 
 } // !IN_LLVM
 
-// IN_LLVM replaced: `private` by `extern (C++)`
-extern (C++) void printPredefinedVersions()
+private void printPredefinedVersions()
 {
     if (global.params.verbose && global.versionids)
     {

dmd/mars.h

@@ -102,7 +102,6 @@ void ensurePathToNameExists(Loc loc, const char *name);
 
 #if IN_LLVM
 int mars_mainBody(Strings &files, Strings &libmodules);
-void printPredefinedVersions();
 #endif
 
 const char *importHint(const char *s);

driver/main.cpp

@@ -1123,7 +1123,6 @@ int cppmain(int argc, char **argv) {
 
 void addDefaultVersionIdentifiers() {
   registerPredefinedVersions();
-  printPredefinedVersions();
 }
 
 void codegenModules(Modules &modules) {