Add SPDX license identifiers to source files under the LGPL

This follows what the kernel is doing, c.f.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5fd54ace4721fc5ce2bb5aef6318fcf17f421460.

27 files changed, 27 insertions, 0 deletions

diff --git a/src/systemd/_sd-common.h b/src/systemd/_sd-common.h
index 97c3943861..b4400e7b36 100644
--- a/src/systemd/_sd-common.h
+++ b/src/systemd/_sd-common.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdcommonhfoo
 #define foosdcommonhfoo
 
diff --git a/src/systemd/sd-bus-protocol.h b/src/systemd/sd-bus-protocol.h
index 623cee0c50..63e3702fbf 100644
--- a/src/systemd/sd-bus-protocol.h
+++ b/src/systemd/sd-bus-protocol.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdbusprotocolhfoo
 #define foosdbusprotocolhfoo
 
diff --git a/src/systemd/sd-bus-vtable.h b/src/systemd/sd-bus-vtable.h
index 1e82cae038..f6fb40fbb5 100644
--- a/src/systemd/sd-bus-vtable.h
+++ b/src/systemd/sd-bus-vtable.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdbusvtablehfoo
 #define foosdbusvtablehfoo
 
diff --git a/src/systemd/sd-bus.h b/src/systemd/sd-bus.h
index ae299a3dae..c5c7096d55 100644
--- a/src/systemd/sd-bus.h
+++ b/src/systemd/sd-bus.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdbushfoo
 #define foosdbushfoo
 
diff --git a/src/systemd/sd-daemon.h b/src/systemd/sd-daemon.h
index 8c096f610f..61cfdd8e0a 100644
--- a/src/systemd/sd-daemon.h
+++ b/src/systemd/sd-daemon.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosddaemonhfoo
 #define foosddaemonhfoo
 
diff --git a/src/systemd/sd-device.h b/src/systemd/sd-device.h
index c1d07561d7..6ac0b13c0c 100644
--- a/src/systemd/sd-device.h
+++ b/src/systemd/sd-device.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosddevicehfoo
 #define foosddevicehfoo
 
diff --git a/src/systemd/sd-dhcp-client.h b/src/systemd/sd-dhcp-client.h
index 5e46d8d0e8..6eb9eb61a8 100644
--- a/src/systemd/sd-dhcp-client.h
+++ b/src/systemd/sd-dhcp-client.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosddhcpclienthfoo
 #define foosddhcpclienthfoo
 
diff --git a/src/systemd/sd-dhcp-lease.h b/src/systemd/sd-dhcp-lease.h
index 7ab99cccd1..3cc7fcabe3 100644
--- a/src/systemd/sd-dhcp-lease.h
+++ b/src/systemd/sd-dhcp-lease.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosddhcpleasehfoo
 #define foosddhcpleasehfoo
 
diff --git a/src/systemd/sd-dhcp-server.h b/src/systemd/sd-dhcp-server.h
index d4517a26d6..9d39e43b98 100644
--- a/src/systemd/sd-dhcp-server.h
+++ b/src/systemd/sd-dhcp-server.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosddhcpserverhfoo
 #define foosddhcpserverhfoo
 
diff --git a/src/systemd/sd-dhcp6-client.h b/src/systemd/sd-dhcp6-client.h
index 0749c05c51..37803c71d8 100644
--- a/src/systemd/sd-dhcp6-client.h
+++ b/src/systemd/sd-dhcp6-client.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosddhcp6clienthfoo
 #define foosddhcp6clienthfoo
 
diff --git a/src/systemd/sd-dhcp6-lease.h b/src/systemd/sd-dhcp6-lease.h
index 184fbb8e0d..5807b1836b 100644
--- a/src/systemd/sd-dhcp6-lease.h
+++ b/src/systemd/sd-dhcp6-lease.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosddhcp6leasehfoo
 #define foosddhcp6leasehfoo
 
diff --git a/src/systemd/sd-event.h b/src/systemd/sd-event.h
index f8cb895660..9083d5fa9e 100644
--- a/src/systemd/sd-event.h
+++ b/src/systemd/sd-event.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdeventhfoo
 #define foosdeventhfoo
 
diff --git a/src/systemd/sd-hwdb.h b/src/systemd/sd-hwdb.h
index 7105920492..fd69aaf3d4 100644
--- a/src/systemd/sd-hwdb.h
+++ b/src/systemd/sd-hwdb.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdhwdbhfoo
 #define foosdhwdbhfoo
 
diff --git a/src/systemd/sd-id128.h b/src/systemd/sd-id128.h
index 9b38969b77..67fc595669 100644
--- a/src/systemd/sd-id128.h
+++ b/src/systemd/sd-id128.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdid128hfoo
 #define foosdid128hfoo
 
diff --git a/src/systemd/sd-ipv4acd.h b/src/systemd/sd-ipv4acd.h
index 16d99983a8..677ae3b216 100644
--- a/src/systemd/sd-ipv4acd.h
+++ b/src/systemd/sd-ipv4acd.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdipv4acdfoo
 #define foosdipv4acdfoo
 
diff --git a/src/systemd/sd-ipv4ll.h b/src/systemd/sd-ipv4ll.h
index 5ba92083f4..c330b0ae9e 100644
--- a/src/systemd/sd-ipv4ll.h
+++ b/src/systemd/sd-ipv4ll.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdipv4llfoo
 #define foosdipv4llfoo
 
diff --git a/src/systemd/sd-journal.h b/src/systemd/sd-journal.h
index 9c36b27157..2a70d5e818 100644
--- a/src/systemd/sd-journal.h
+++ b/src/systemd/sd-journal.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdjournalhfoo
 #define foosdjournalhfoo
 
diff --git a/src/systemd/sd-lldp.h b/src/systemd/sd-lldp.h
index 3f35eebea3..0a76fa6314 100644
--- a/src/systemd/sd-lldp.h
+++ b/src/systemd/sd-lldp.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdlldphfoo
 #define foosdlldphfoo
 
diff --git a/src/systemd/sd-login.h b/src/systemd/sd-login.h
index e3ecbd8378..d8e2c6822d 100644
--- a/src/systemd/sd-login.h
+++ b/src/systemd/sd-login.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdloginhfoo
 #define foosdloginhfoo
 
diff --git a/src/systemd/sd-messages.h b/src/systemd/sd-messages.h
index 8c23486779..874329ff8c 100644
--- a/src/systemd/sd-messages.h
+++ b/src/systemd/sd-messages.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdmessageshfoo
 #define foosdmessageshfoo
 
diff --git a/src/systemd/sd-ndisc.h b/src/systemd/sd-ndisc.h
index 9f7d4ef71a..152114507a 100644
--- a/src/systemd/sd-ndisc.h
+++ b/src/systemd/sd-ndisc.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdndiscfoo
 #define foosdndiscfoo
 
diff --git a/src/systemd/sd-netlink.h b/src/systemd/sd-netlink.h
index b28fc0da00..d6e3816c64 100644
--- a/src/systemd/sd-netlink.h
+++ b/src/systemd/sd-netlink.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdnetlinkhfoo
 #define foosdnetlinkhfoo
 
diff --git a/src/systemd/sd-network.h b/src/systemd/sd-network.h
index 0f13e2bae7..7f5a6bd3fa 100644
--- a/src/systemd/sd-network.h
+++ b/src/systemd/sd-network.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdnetworkhfoo
 #define foosdnetworkhfoo
 
diff --git a/src/systemd/sd-path.h b/src/systemd/sd-path.h
index be6abdcd03..2dfc8967b4 100644
--- a/src/systemd/sd-path.h
+++ b/src/systemd/sd-path.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdpathhfoo
 #define foosdpathhfoo
 
diff --git a/src/systemd/sd-radv.h b/src/systemd/sd-radv.h
index 9805e3f24d..94d5e71e8a 100644
--- a/src/systemd/sd-radv.h
+++ b/src/systemd/sd-radv.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdradvfoo
 #define foosdradvfoo
 
diff --git a/src/systemd/sd-resolve.h b/src/systemd/sd-resolve.h
index 1c792dab39..14d0cbde04 100644
--- a/src/systemd/sd-resolve.h
+++ b/src/systemd/sd-resolve.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdresolvehfoo
 #define foosdresolvehfoo
 
diff --git a/src/systemd/sd-utf8.h b/src/systemd/sd-utf8.h
index 6781983878..cd02c6a296 100644
--- a/src/systemd/sd-utf8.h
+++ b/src/systemd/sd-utf8.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #ifndef foosdutf8hfoo
 #define foosdutf8hfoo