diff --git a/src/plugins/perl/CMakeLists.txt b/src/plugins/perl/CMakeLists.txt
index 0cb46d4d7..aab4f2297 100644
--- a/src/plugins/perl/CMakeLists.txt
+++ b/src/plugins/perl/CMakeLists.txt
@@ -26,8 +26,8 @@ set_target_properties(perl PROPERTIES PREFIX "")
 if(PERL_FOUND)
   if(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
     # remove "-arch xxx" on macOS
-    STRING(REGEX REPLACE "-arch ppc|-arch i386|-arch x86_64" "" PERL_CFLAGS "${PERL_CFLAGS}")
-    STRING(REGEX REPLACE "-arch ppc|-arch i386|-arch x86_64" "" PERL_LFLAGS "${PERL_LFLAGS}")
+    string(REGEX REPLACE "-arch ppc|-arch i386|-arch x86_64" "" PERL_CFLAGS "${PERL_CFLAGS}")
+    string(REGEX REPLACE "-arch ppc|-arch i386|-arch x86_64" "" PERL_LFLAGS "${PERL_LFLAGS}")
   endif()
   add_definitions(${PERL_CFLAGS})
   include_directories(${PERL_INCLUDE_PATH})