diff --git a/contrib/libzlib-ng/CMakeLists.txt b/contrib/libzlib-ng/CMakeLists.txt
index e037294090f..6c443322923 100644
--- a/contrib/libzlib-ng/CMakeLists.txt
+++ b/contrib/libzlib-ng/CMakeLists.txt
@@ -337,7 +337,7 @@ if(WITH_OPTIM)
         add_definitions(-DX86_SSE4_2_CRC_HASH)
         set(ZLIB_ARCH_SRCS ${ZLIB_ARCH_SRCS} ${ARCHDIR}/insert_string_sse.c)
         add_feature_info(SSE4_CRC 1 "Support CRC hash generation using the SSE4.2 instruction set, using \"${SSE4FLAG}\"")
-        add_intrinsics_option(${SSE4FLAG})
+        add_intrinsics_option("${SSE4FLAG}")
         if(WITH_NEW_STRATEGIES)
             add_definitions(-DX86_QUICK_STRATEGY)
             set(ZLIB_ARCH_SRCS ${ZLIB_ARCH_SRCS} ${ARCHDIR}/deflate_quick.c)
@@ -348,16 +348,16 @@ if(WITH_OPTIM)
         add_definitions(-DX86_SSE2_FILL_WINDOW)
         set(ZLIB_ARCH_SRCS ${ZLIB_ARCH_SRCS} ${ARCHDIR}/fill_window_sse.c)
         if(NOT ${ARCH} MATCHES "x86_64")
-            add_intrinsics_option(${SSE2FLAG})
+            add_intrinsics_option("${SSE2FLAG}")
         endif()
     endif()
     if(HAVE_PCLMULQDQ_INTRIN)
         add_definitions(-DX86_PCLMULQDQ_CRC)
         set(ZLIB_ARCH_SRCS ${ZLIB_ARCH_SRCS} ${ARCHDIR}/crc_folding.c)
         add_feature_info(PCLMUL_CRC 1 "Support CRC hash generation using PCLMULQDQ, using \"${SSE4FLAG} ${PCLMULFLAG}\"")
-        add_intrinsics_option(${PCLMULFLAG})
+        add_intrinsics_option("${PCLMULFLAG}")
         if(NOT HAVE_SSE42_INTRIN)
-            add_intrinsics_option(${SSE4FLAG})
+            add_intrinsics_option("${SSE4FLAG}")
         endif()
     endif()
 endif()