[lld-macho] Have all load commands aligned to the word size

This is what ld64 does, and also what we already do for most of the
other load commands. I'm not aware of a good way to test this, but I
don't think it really matters.

Differential Revision: https://reviews.llvm.org/D141462

Author: int3

lld/MachO/Writer.cpp

@@ -328,7 +328,8 @@ class LCDylib final : public LoadCommand {
   }
 
   uint32_t getSize() const override {
-    return alignTo(sizeof(dylib_command) + path.size() + 1, 8);
+    return alignToPowerOf2(sizeof(dylib_command) + path.size() + 1,
+                           target->wordSize);
   }
 
   void writeTo(uint8_t *buf) const override {
@@ -362,7 +363,8 @@ uint32_t LCDylib::instanceCount = 0;
 class LCLoadDylinker final : public LoadCommand {
 public:
   uint32_t getSize() const override {
-    return alignTo(sizeof(dylinker_command) + path.size() + 1, 8);
+    return alignToPowerOf2(sizeof(dylinker_command) + path.size() + 1,
+                           target->wordSize);
   }
 
   void writeTo(uint8_t *buf) const override {