diff --git a/CMakeLists.txt b/CMakeLists.txt
index dfb1c13..3db4d7d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -117,13 +117,13 @@ if(NOT MSVC)
     target_link_libraries(snmalloc_lib INTERFACE atomic)
   endif()
   if(${CMAKE_SYSTEM_PROCESSOR} STREQUAL "x86_64")
-   target_compile_options(snmalloc_lib INTERFACE -mcx16)
+   target_compile_options(snmalloc_lib INTERFACE $<$<COMPILE_LANGUAGE:CXX>:-mcx16>)
   elseif(${CMAKE_SYSTEM_PROCESSOR} STREQUAL "amd64")
-   target_compile_options(snmalloc_lib INTERFACE -mcx16)
+   target_compile_options(snmalloc_lib INTERFACE $<$<COMPILE_LANGUAGE:CXX>:-mcx16>)
   elseif(${CMAKE_SYSTEM_PROCESSOR} STREQUAL "AMD64")
-   target_compile_options(snmalloc_lib INTERFACE -mcx16)
+   target_compile_options(snmalloc_lib INTERFACE $<$<COMPILE_LANGUAGE:CXX>:-mcx16>)
   elseif(${CMAKE_SYSTEM_PROCESSOR} STREQUAL "x86")
-   target_compile_options(snmalloc_lib INTERFACE -mcx16)
+   target_compile_options(snmalloc_lib INTERFACE $<$<COMPILE_LANGUAGE:CXX>:-mcx16>)
   # XXX elseif ARM?
   endif()
 endif()
@@ -143,13 +143,13 @@ endif()
 
 if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
   if(${CMAKE_SYSTEM_PROCESSOR} STREQUAL "x86_64")
-    target_compile_options(snmalloc_lib INTERFACE -mcx16)
+    target_compile_options(snmalloc_lib INTERFACE $<$<COMPILE_LANGUAGE:CXX>:-mcx16>)
   elseif(${CMAKE_SYSTEM_PROCESSOR} STREQUAL "amd64")
-   target_compile_options(snmalloc_lib INTERFACE -mcx16)
+   target_compile_options(snmalloc_lib INTERFACE $<$<COMPILE_LANGUAGE:CXX>:-mcx16>)
   elseif(${CMAKE_SYSTEM_PROCESSOR} STREQUAL "AMD64")
-   target_compile_options(snmalloc_lib INTERFACE -mcx16)
+   target_compile_options(snmalloc_lib INTERFACE $<$<COMPILE_LANGUAGE:CXX>:-mcx16>)
   elseif(${CMAKE_SYSTEM_PROCESSOR} STREQUAL "x86")
-   target_compile_options(snmalloc_lib INTERFACE -mcx16)
+   target_compile_options(snmalloc_lib INTERFACE $<$<COMPILE_LANGUAGE:CXX>:-mcx16>)
   endif()
 endif ()