diff --git a/sysdeps/unix/bsd/sun/sunos4/system.c b/sysdeps/unix/bsd/sun/sunos4/system.c
new file mode 100644
index 0000000000..2c8e634bc8
--- /dev/null
+++ b/sysdeps/unix/bsd/sun/sunos4/system.c
@@ -0,0 +1,2 @@
+/* SunOS 4 does have `waitpid'.  Avoid unix/system.c, which says we don't.  */
+#include <sysdeps/posix/system.c>
diff --git a/sysdeps/unix/bsd/ultrix4/system.c b/sysdeps/unix/bsd/ultrix4/system.c
new file mode 100644
index 0000000000..b133fe77c0
--- /dev/null
+++ b/sysdeps/unix/bsd/ultrix4/system.c
@@ -0,0 +1,2 @@
+/* Ultrix 4 does have `waitpid'.  Avoid unix/system.c, which says we don't.  */
+#include <sysdeps/posix/system.c>
diff --git a/sysdeps/unix/sysv/sysv4/system.c b/sysdeps/unix/sysv/sysv4/system.c
new file mode 100644
index 0000000000..fbfe43f19a
--- /dev/null
+++ b/sysdeps/unix/sysv/sysv4/system.c
@@ -0,0 +1,2 @@
+/* SVR4 does have `waitpid'.  Avoid unix/system.c, which says we don't.  */
+#include <sysdeps/posix/system.c>