fix clang -Wunused-value warnings for error functions

diff --git a/cache.h b/cache.h
index 0e8e5d8002724451e1229bd61460486ac1d04cbd..98b62bcb5ae0c95db95a971bfa9ccaa2b1fcc8a0 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -1136,7 +1136,7 @@ extern int check_repository_format_version(const char *var, const char *value, v
 extern int git_env_bool(const char *, int);
 extern int git_config_system(void);
 extern int config_error_nonbool(const char *);
-#ifdef __GNUC__
+#if defined(__GNUC__) && ! defined(__clang__)
 #define config_error_nonbool(s) (config_error_nonbool(s), -1)
 #endif
 extern const char *get_log_output_encoding(void);