`_RUBY_DEBUG_LOG` usable anywhere

even if `USE_RUBY_DEBUG_LOG=0`.
It becomes `fprintf(stderr, ...)`.

1 files changed, 18 insertions, 0 deletions

diff --git a/debug.c b/debug.c
index b92faa8f36..4daee2bd1c 100644
--- a/debug.c
+++ b/debug.c
@@ -708,4 +708,22 @@ ruby_debug_log_dump(const char *fname, unsigned int n)
         fclose(fp);
     }
 }
+
+#else
+
+#undef ruby_debug_log
+void
+ruby_debug_log(const char *file, int line, const char *func_name, const char *fmt, ...)
+{
+    va_list args;
+
+    fprintf(stderr, "[%s:%d] %s: ", file, line, func_name);
+
+    va_start(args, fmt);
+    vfprintf(stderr, fmt, args);
+    va_end(args);
+
+    fprintf(stderr, "\n");
+}
+
 #endif // #if USE_RUBY_DEBUG_LOG