diff --git a/Makefile b/Makefile
index 93664d6714..1d4c02e59d 100644
--- a/Makefile
+++ b/Makefile
@@ -2270,9 +2270,10 @@ perl_localedir_SQ = $(localedir_SQ)
 
 ifndef NO_PERL
 PERL_HEADER_TEMPLATE = perl/header_templates/fixed_prefix.template.pl
-PERL_DEFINES = $(PERL_PATH_SQ):$(PERLLIB_EXTRA_SQ):$(perllibdir_SQ)
-
-PERL_DEFINES := $(PERL_PATH_SQ) $(PERLLIB_EXTRA_SQ) $(perllibdir_SQ)
+PERL_DEFINES :=
+PERL_DEFINES += $(PERL_PATH_SQ)
+PERL_DEFINES += $(PERLLIB_EXTRA_SQ)
+PERL_DEFINES += $(perllibdir_SQ)
 PERL_DEFINES += $(RUNTIME_PREFIX)
 
 # Support Perl runtime prefix. In this mode, a different header is installed