diff --git a/lib/base/context.c b/lib/base/context.c
index bbbb7ed89..c16bc1014 100644
--- a/lib/base/context.c
+++ b/lib/base/context.c
@@ -176,7 +176,9 @@ heim_set_debug_dest(heim_context context, heim_log_facility *fac)
     return 0;
 }
 
-#define PATH_SEP ":"
+#ifndef PATH_SEP
+# define PATH_SEP ":"
+#endif
 
 static heim_error_code
 add_file(char ***pfilenames, int *len, char *file)
diff --git a/lib/hx509/cert.c b/lib/hx509/cert.c
index 6cb871d96..5f9b3fa37 100644
--- a/lib/hx509/cert.c
+++ b/lib/hx509/cert.c
@@ -125,7 +125,9 @@ hx509_get_instance(const char *libname)
     return 0;
 }
 
-#define PATH_SEP ":"
+#ifndef PATH_SEP
+# define PATH_SEP ":"
+#endif
 static const char *hx509_config_file =
 "~/.hx509/config" PATH_SEP
 SYSCONFDIR "/hx509.conf" PATH_SEP