diff --git a/drivers/filesystems/cdfs/CMakeLists.txt b/drivers/filesystems/cdfs/CMakeLists.txt
index 2f1d4526c3e..3e35991bfa0 100644
--- a/drivers/filesystems/cdfs/CMakeLists.txt
+++ b/drivers/filesystems/cdfs/CMakeLists.txt
@@ -38,3 +38,9 @@ target_link_libraries(cdfs ${PSEH_LIB} memcmp)
 add_importlibs(cdfs ntoskrnl hal)
 add_cd_file(TARGET cdfs DESTINATION reactos/system32/drivers NO_CAB FOR all)
 add_registry_inf(cdfs_reg.inf)
+
+if (CLANG AND GCC)
+    # Make __inline work as expected
+    target_compile_options(cdfs PRIVATE -std=gnu89)
+endif()
+