diff --git a/build/luajit-buildvm/luajit-buildvm.vcxproj b/build/luajit-buildvm/luajit-buildvm.vcxproj
index f69756765..bb8f84b58 100644
--- a/build/luajit-buildvm/luajit-buildvm.vcxproj
+++ b/build/luajit-buildvm/luajit-buildvm.vcxproj
@@ -21,7 +21,11 @@
   </PropertyGroup>
   <ItemDefinitionGroup>
     <ClCompile>
-      <PreprocessorDefinitions>_CRT_SECURE_NO_WARNINGS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>
+        _CRT_SECURE_NO_WARNINGS;
+        LUAJIT_ENABLE_LUA52COMPAT;
+        %(PreprocessorDefinitions)
+      </PreprocessorDefinitions>
       <AdditionalIncludeDirectories>
         $(AegisubObjectDir);
         $(SrcDir)dynasm;
diff --git a/build/luajit/luajit.vcxproj b/build/luajit/luajit.vcxproj
index 81169e2eb..40bcdea16 100644
--- a/build/luajit/luajit.vcxproj
+++ b/build/luajit/luajit.vcxproj
@@ -17,7 +17,11 @@
   <!-- Project specific configuration -->
   <ItemDefinitionGroup>
     <ClCompile>
-      <PreprocessorDefinitions>_CRT_SECURE_NO_WARNINGS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>
+        _CRT_SECURE_NO_WARNINGS;
+        LUAJIT_ENABLE_LUA52COMPAT;
+        %(PreprocessorDefinitions)
+      </PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(AegisubObjectDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
     </ClCompile>
   </ItemDefinitionGroup>
@@ -329,4 +333,4 @@
       <Project>{7ca6a4eb-a11b-4975-8f3a-f633111c6213}</Project>
     </ProjectReference>
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>