diff --git a/win32/win32.c b/win32/win32.c
index ac8319529b..59040824ad 100644
--- a/win32/win32.c
+++ b/win32/win32.c
@@ -77,6 +77,7 @@ static char *w32_getenv(const char *name, UINT cp);
 #define DLN_FIND_EXTRA_ARG_DECL ,UINT cp
 #define DLN_FIND_EXTRA_ARG ,cp
 #define rb_w32_stati128(path, st) w32_stati128(path, st, cp, FALSE)
+#define getenv(name) w32_getenv(name, cp) /* Necessarily For dln.c */
 #undef CharNext
 #define CharNext(p) CharNextExA(cp, (p), 0)
 #define dln_find_exe_r rb_w32_udln_find_exe_r