diff --git a/recipes/libs/libmodplug1/recipe.toml b/recipes/libs/libmodplug1/recipe.toml
index 772a29287..e7fe9552b 100644
--- a/recipes/libs/libmodplug1/recipe.toml
+++ b/recipes/libs/libmodplug1/recipe.toml
@@ -9,5 +9,7 @@ autotools_recursive_regenerate
 template = "custom"
 script = """
 DYNAMIC_INIT
+# For strings.h from string.h
+export CPPFLAGS="${CPPFLAGS} -D_GNU_SOURCE"
 cookbook_configure
 """