fix warnings in coreclr/jit/compiler.cpp for non-Windows targets

This change was extracted from dotnet/runtimelab#2614,
which includes various fixes to enable building on non-Windows systems.  We're
in the process of upstreaming the parts of that PR which are not specific to
NativeAOT-LLVM, and this is the latest such change.

Signed-off-by: Joel Dice <joel.dice@fermyon.com>

src/coreclr/jit/compiler.cpp

@@ -1447,7 +1447,7 @@ void DisplayNowayAssertMap()
 
         for (i = 0; i < count; i++)
         {
-            fprintf(fout, "%u, %s, %u, \"%s\"\n", nacp[i].count, nacp[i].fl.m_file, nacp[i].fl.m_line,
+            fprintf(fout, "%zu, %s, %u, \"%s\"\n", nacp[i].count, nacp[i].fl.m_file, nacp[i].fl.m_line,
                     nacp[i].fl.m_condStr);
         }
 
@@ -3305,7 +3305,7 @@ void Compiler::compInitOptions(JitFlags* jitFlags)
         compMaxUncheckedOffsetForNullObject = (size_t)JitConfig.JitMaxUncheckedOffset();
         if (verbose)
         {
-            printf("STRESS_NULL_OBJECT_CHECK: compMaxUncheckedOffsetForNullObject=0x%X\n",
+            printf("STRESS_NULL_OBJECT_CHECK: compMaxUncheckedOffsetForNullObject=0x%zX\n",
                    compMaxUncheckedOffsetForNullObject);
         }
     }
@@ -9351,7 +9351,7 @@ void dumpConvertedVarSet(Compiler* comp, VARSET_VALARG_TP vars)
 
     bool first = true;
     printf("{");
-    for (size_t varNum = 0; varNum < comp->lvaCount; varNum++)
+    for (unsigned varNum = 0; varNum < comp->lvaCount; varNum++)
     {
         if (pVarNumSet[varNum] == 1)
         {