Quote ';' so it makes it into the output.
diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index e409940..e442c10 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -196,7 +196,7 @@
 set(zip_err_str [=[
 /*
    This file was generated automatically by CMake
-   from zip.h; make changes there.
+   from zip.h\; make changes there.
  */
 
 #include "zipint.h"