libdrgn: move string_builder_line_break() to string_builder.c

libdrgn/linux_kernel.c

@@ -1040,17 +1040,6 @@ open_kernel_module_debug_info(struct drgn_program *prog,
 	return &drgn_stop;
 }
 
-/*
- * Append a newline character if the string isn't empty and doesn't already end
- * in a newline.
- */
-static bool string_builder_line_break(struct string_builder *sb)
-{
-	if (!sb->len || sb->str[sb->len - 1] == '\n')
-		return true;
-	return string_builder_appendc(sb, '\n');
-}
-
 static struct drgn_error *
 open_loaded_kernel_modules(struct drgn_program *prog,
 			   struct string_builder *missing_debug_info)

libdrgn/string_builder.c

@@ -86,3 +86,10 @@ bool string_builder_appendf(struct string_builder *sb, const char *format, ...)
 	va_end(ap);
 	return ret;
 }
+
+bool string_builder_line_break(struct string_builder *sb)
+{
+	if (!sb->len || sb->str[sb->len - 1] == '\n')
+		return true;
+	return string_builder_appendc(sb, '\n');
+}

libdrgn/string_builder.h

@@ -144,6 +144,16 @@ bool string_builder_appendf(struct string_builder *sb, const char *format, ...)
 bool string_builder_vappendf(struct string_builder *sb, const char *format,
 			     va_list ap);
 
+/**
+ * Append a newline character to a @ref string_builder if the string isn't empty
+ * and doesn't already end in a newline.
+ *
+ * @param[in] sb String builder.
+ * @return @c true on success, @c false on error (if we couldn't allocate
+ * memory).
+ */
+bool string_builder_line_break(struct string_builder *sb);
+
 /**
  * Callback to append to a string later.
  *