diff --git a/tests/sys_procfs_test.cpp b/tests/sys_procfs_test.cpp
index 5e0a0b0..4a64742 100644
--- a/tests/sys_procfs_test.cpp
+++ b/tests/sys_procfs_test.cpp
@@ -16,6 +16,7 @@
 
 #include <gtest/gtest.h>
 
+#include <ucontext.h> // for NGREG on musl
 #include <sys/procfs.h>
 
 TEST(sys_procfs, types) {