Add quotes to the poppler version define
diff --git a/poppler/poppler-config.h.cmake b/poppler/poppler-config.h.cmake
index 40a3c4a..94a12aa 100644
--- a/poppler/poppler-config.h.cmake
+++ b/poppler/poppler-config.h.cmake
@@ -16,7 +16,7 @@
 
 /* Defines the poppler version */
 #ifndef POPPLER_VERSION
-#define POPPLER_VERSION ${POPPLER_VERSION}
+#define POPPLER_VERSION "${POPPLER_VERSION}"
 #endif
 
 /* Enable multithreading support. */