[NFC][InferAlignment] Swap extern declaration and definition of EnableInferAlignmentPass

This prevents a linker issue when only InstCombine is linked without
PassBuilder, like in the case of bugpoint.

Author: dc03

llvm/lib/Passes/PassBuilderPipelines.cpp

@@ -275,10 +275,7 @@ cl::opt<bool> EnableMemProfContextDisambiguation(
     "enable-memprof-context-disambiguation", cl::init(false), cl::Hidden,
     cl::ZeroOrMore, cl::desc("Enable MemProf context disambiguation"));
 
-cl::opt<bool> EnableInferAlignmentPass(
-    "enable-infer-alignment-pass", cl::init(true), cl::Hidden, cl::ZeroOrMore,
-    cl::desc("Enable the InferAlignment pass, disabling alignment inference in "
-             "InstCombine"));
+extern cl::opt<bool> EnableInferAlignmentPass;
 
 PipelineTuningOptions::PipelineTuningOptions() {
   LoopInterleaving = true;

llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp

@@ -36,7 +36,10 @@ static cl::opt<unsigned> MaxCopiedFromConstantUsers(
     cl::desc("Maximum users to visit in copy from constant transform"),
     cl::Hidden);
 
-extern cl::opt<bool> EnableInferAlignmentPass;
+cl::opt<bool> EnableInferAlignmentPass(
+    "enable-infer-alignment-pass", cl::init(true), cl::Hidden, cl::ZeroOrMore,
+    cl::desc("Enable the InferAlignment pass, disabling alignment inference in "
+             "InstCombine"));
 
 /// isOnlyCopiedFromConstantMemory - Recursively walk the uses of a (derived)
 /// pointer to an alloca.  Ignore any reads of the pointer, return false if we