diff --git a/recipes/oniguruma.toml b/recipes/oniguruma.toml
index 84724d51..34fc6b92 100644
--- a/recipes/oniguruma.toml
+++ b/recipes/oniguruma.toml
@@ -16,4 +16,6 @@ link     = "static"
 flags    = []
 
 [build.phases]
-configure = "./configure --prefix=/usr --enable-posix-api=yes"
+# el tarball extrae src/ sin permiso de escritura p/ el uid del sandbox ⇒ config.status no puede crear
+# src/Makefile. chmod -R u+w antes de configure (inocuo, sólo permisos).
+configure = "chmod -R u+w . && ./configure --prefix=/usr --enable-posix-api=yes"