diff --git a/lib/libspl/include/sys/Makefile.am b/lib/libspl/include/sys/Makefile.am
index ca2963499c..a6c2742683 100644
--- a/lib/libspl/include/sys/Makefile.am
+++ b/lib/libspl/include/sys/Makefile.am
@@ -13,6 +13,7 @@ libspl_HEADERS = \
 	$(top_srcdir)/lib/libspl/include/sys/debug.h \
 	$(top_srcdir)/lib/libspl/include/sys/dkio.h \
 	$(top_srcdir)/lib/libspl/include/sys/dklabel.h \
+	$(top_srcdir)/lib/libspl/include/sys/errno.h \
 	$(top_srcdir)/lib/libspl/include/sys/feature_tests.h \
 	$(top_srcdir)/lib/libspl/include/sys/file.h \
 	$(top_srcdir)/lib/libspl/include/sys/frame.h \
@@ -31,8 +32,10 @@ libspl_HEADERS = \
 	$(top_srcdir)/lib/libspl/include/sys/note.h \
 	$(top_srcdir)/lib/libspl/include/sys/param.h \
 	$(top_srcdir)/lib/libspl/include/sys/policy.h \
+	$(top_srcdir)/lib/libspl/include/sys/poll.h \
 	$(top_srcdir)/lib/libspl/include/sys/priv.h \
 	$(top_srcdir)/lib/libspl/include/sys/processor.h \
+	$(top_srcdir)/lib/libspl/include/sys/signal.h \
 	$(top_srcdir)/lib/libspl/include/sys/stack.h \
 	$(top_srcdir)/lib/libspl/include/sys/stat.h \
 	$(top_srcdir)/lib/libspl/include/sys/stropts.h \
diff --git a/lib/libspl/include/sys/errno.h b/lib/libspl/include/sys/errno.h
new file mode 100644
index 0000000000..e8bfbe3538
--- /dev/null
+++ b/lib/libspl/include/sys/errno.h
@@ -0,0 +1,35 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (the "License").  You may not use this file except in compliance
+ * with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2017 Zettabyte Software, LLC.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+/*
+ * Compiling against musl correctly points out that including sys/errno.h is
+ * disallowed by the Single UNIX Specification when building in userspace, so
+ * we implement a dummy header to redirect the include to the proper header.
+ */
+#ifndef _LIBSPL_SYS_ERRNO_H
+#define	_LIBSPL_SYS_ERRNO_H
+#include <errno.h>
+#endif /* _LIBSPL_SYS_ERRNO_H */
diff --git a/lib/libspl/include/sys/poll.h b/lib/libspl/include/sys/poll.h
new file mode 100644
index 0000000000..6ab0bddc0b
--- /dev/null
+++ b/lib/libspl/include/sys/poll.h
@@ -0,0 +1,41 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (the "License").  You may not use this file except in compliance
+ * with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2017 Zettabyte Software, LLC.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+/*
+ * Compiling against musl correctly points out that including sys/poll.h is
+ * disallowed by the Single UNIX Specification when building in userspace. We
+ * implement a dummy header to redirect the include to the proper header.
+ * However, glibc, klibc and uclibc break this shim by including sys/poll.h
+ * from poll.h, so we add explicit exceptions for them.
+ */
+#ifndef _LIBSPL_SYS_POLL_H
+#define	_LIBSPL_SYS_POLL_H
+#if defined(__GLIBC__) || defined(__KLIBC__) || defined(__UCLIBC__)
+#include_next <sys/poll.h>
+#else
+#include <poll.h>
+#endif
+#endif /* _LIBSPL_SYS_POLL_H */
diff --git a/lib/libspl/include/sys/signal.h b/lib/libspl/include/sys/signal.h
new file mode 100644
index 0000000000..df9221a694
--- /dev/null
+++ b/lib/libspl/include/sys/signal.h
@@ -0,0 +1,35 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (the "License").  You may not use this file except in compliance
+ * with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2017 Zettabyte Software, LLC.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+/*
+ * Compiling against musl correctly points out that including sys/signal.h is
+ * disallowed by the Single UNIX Specification when building in userspace, so
+ * we implement a dummy header to redirect the include to the proper header.
+ */
+#ifndef _LIBSPL_SYS_SIGNAL_H
+#define	_LIBSPL_SYS_SIGNAL_H
+#include <signal.h>
+#endif /* _LIBSPL_SYS_SIGNAL_H */
diff --git a/lib/libzfs/libzfs_util.c b/lib/libzfs/libzfs_util.c
index 4e83326087..e9119e11de 100644
--- a/lib/libzfs/libzfs_util.c
+++ b/lib/libzfs/libzfs_util.c
@@ -44,7 +44,7 @@
 #include <sys/mnttab.h>
 #include <sys/mntent.h>
 #include <sys/types.h>
-#include <wait.h>
+#include <sys/wait.h>
 
 #include <libzfs.h>
 #include <libzfs_core.h>
diff --git a/tests/zfs-tests/cmd/file_trunc/file_trunc.c b/tests/zfs-tests/cmd/file_trunc/file_trunc.c
index 38e36c9d49..f9431300be 100644
--- a/tests/zfs-tests/cmd/file_trunc/file_trunc.c
+++ b/tests/zfs-tests/cmd/file_trunc/file_trunc.c
@@ -35,10 +35,8 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <sys/types.h>
-#include <sys/fcntl.h>
 #include <sys/stat.h>
 #include <sys/statvfs.h>
-#include <sys/errno.h>
 #include <sys/time.h>
 #include <sys/ioctl.h>
 #include <sys/wait.h>
diff --git a/tests/zfs-tests/cmd/mktree/mktree.c b/tests/zfs-tests/cmd/mktree/mktree.c
index 95d31a6527..3dc3dd8ec6 100644
--- a/tests/zfs-tests/cmd/mktree/mktree.c
+++ b/tests/zfs-tests/cmd/mktree/mktree.c
@@ -24,6 +24,7 @@
  * Use is subject to license terms.
  */
 
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
@@ -32,7 +33,6 @@
 #include <attr/xattr.h>
 #include <sys/stat.h>
 #include <sys/types.h>
-#include <sys/errno.h>
 #include <sys/param.h>
 
 #define	TYPE_D 'D'