diff --git a/libretro-common/file/config_file.c b/libretro-common/file/config_file.c
index 2f4bbff790..1b0e730cef 100644
--- a/libretro-common/file/config_file.c
+++ b/libretro-common/file/config_file.c
@@ -617,7 +617,7 @@ bool config_get_int(config_file_t *conf, const char *key, int *in)
    return entry != NULL && errno == 0;
 }
 
-#ifndef C89_BUILD
+#if defined(__STDC_VERSION__) && __STDC_VERSION__>=199901L
 bool config_get_uint64(config_file_t *conf, const char *key, uint64_t *in)
 {
    const struct config_entry_list *entry = config_get_entry(conf, key, NULL);
diff --git a/libretro-common/include/file/config_file.h b/libretro-common/include/file/config_file.h
index 710c6e06dc..161ec41022 100644
--- a/libretro-common/include/file/config_file.h
+++ b/libretro-common/include/file/config_file.h
@@ -107,7 +107,7 @@ bool config_get_int(config_file_t *conf, const char *entry, int *in);
 /* Extracts an uint from config file. */
 bool config_get_uint(config_file_t *conf, const char *entry, unsigned *in);
 
-#ifndef C89_BUILD
+#if defined(__STDC_VERSION__) && __STDC_VERSION__>=199901L
 /* Extracts an uint64 from config file. */
 bool config_get_uint64(config_file_t *conf, const char *entry, uint64_t *in);
 #endif