[llvm-objdump][NFC] MachODump.cpp interface cleanup

Continuing from D77388, this patch moves interface declarations
associated with `MachODump.cpp` into the headers corresponding to the
file that defines the variable. At the same time, these externs are
moved into the `llvm::objdump` namespace. The externs defined in
`MachODump.cpp` that are not referenced outside of it are given internal
linkage.

This patch does not rename the external functions defined by
`MachODump.cpp` that are not clearly named as being specific to Mach-O.

Reviewed By: jhenderson, MaskRay

Differential Revision: https://reviews.llvm.org/D77730
diff --git a/llvm/tools/llvm-objdump/MachODump.h b/llvm/tools/llvm-objdump/MachODump.h
index 252b0f4..adf6c34 100644
--- a/llvm/tools/llvm-objdump/MachODump.h
+++ b/llvm/tools/llvm-objdump/MachODump.h
@@ -9,9 +9,21 @@
 #ifndef LLVM_TOOLS_LLVM_OBJDUMP_MACHODUMP_H
 #define LLVM_TOOLS_LLVM_OBJDUMP_MACHODUMP_H
 
+#include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/CommandLine.h"
 
 namespace llvm {
+
+class Error;
+class StringRef;
+
+namespace object {
+class MachOObjectFile;
+class MachOUniversalBinary;
+class ObjectFile;
+class RelocationRef;
+} // namespace object
+
 namespace objdump {
 
 // MachO specific options
@@ -31,6 +43,23 @@
 extern cl::opt<bool> UniversalHeaders;
 extern cl::opt<bool> WeakBind;
 
+Error getMachORelocationValueString(const object::MachOObjectFile *Obj,
+                                    const object::RelocationRef &RelRef,
+                                    llvm::SmallVectorImpl<char> &Result);
+
+void parseInputMachO(StringRef Filename);
+void parseInputMachO(object::MachOUniversalBinary *UB);
+
+void printMachOUnwindInfo(const object::MachOObjectFile *O);
+void printMachOFileHeader(const object::ObjectFile *O);
+void printMachOLoadCommands(const object::ObjectFile *O);
+
+void printExportsTrie(const object::ObjectFile *O);
+void printRebaseTable(object::ObjectFile *O);
+void printBindTable(object::ObjectFile *O);
+void printLazyBindTable(object::ObjectFile *O);
+void printWeakBindTable(object::ObjectFile *O);
+
 } // namespace objdump
 } // namespace llvm