diff --git a/action.yml b/action.yml
index 0bc5ee0..33b3f2e 100644
--- a/action.yml
+++ b/action.yml
@@ -9,7 +9,7 @@ runs:
   using: "composite"
   steps:
     - run: |
-        curl -OL https://github.com/casadi/mockups/releases/download/v79/mockups_${{ inputs.tag }}_Release.zip
+        curl -OL https://github.com/casadi/mockups/releases/download/v80/mockups_${{ inputs.tag }}_Release.zip
         unzip mockups_${{ inputs.tag }}_Release.zip -d mockups
         ls mockups
         ls mockups/cmake
diff --git a/matlab/include/engine.h b/matlab/include/engine.h
index 4f1fb03..b15fe71 100644
--- a/matlab/include/engine.h
+++ b/matlab/include/engine.h
@@ -1,8 +1,10 @@
 #ifndef engine_H
 #define engine_H
 
-extern "C"
-{
+#ifdef __cplusplus
+extern "C" {
+#endif
+
   typedef struct mxArray_tag mxArray;
   typedef struct engine Engine;
 
@@ -14,6 +16,8 @@ extern "C"
   int engPutVariable(Engine *, const char *, const mxArray *);
   int engOutputBuffer(Engine *, char *, int);
 
+#ifdef __cplusplus
 }
+#endif
 
 #endif // engine_H
diff --git a/matlab/include/mex.h b/matlab/include/mex.h
index 501941f..df127bc 100644
--- a/matlab/include/mex.h
+++ b/matlab/include/mex.h
@@ -2,8 +2,10 @@
 #define mex_H
 
 
-extern "C"
-{
+#ifdef __cplusplus
+extern "C" {
+#endif
+
   typedef struct mxArray_tag mxArray;
 
 
@@ -22,6 +24,8 @@ void mexLock(void);
 int mexAtExit(void (*)(void));
 void mexMakeArrayPersistent(mxArray *);
 
+#ifdef __cplusplus
 }
+#endif
 
 #endif // mex_H