diff --git a/makefile b/makefile
index f2e7c2c..c177b25 100644
--- a/makefile
+++ b/makefile
@@ -9,6 +9,12 @@ MINOR_VERSION := 0
 MICRO_VERSION := 1
 
 PREFIX = /usr/local
+SYSCONFDIR = $(PREFIX)/etc
+
+ifeq '$(shell uname)' 'Linux'
+	SYSCONFDIR = /etc
+endif
+
 INSTALL = install
 
 LIBS := wayland-client gtk+-wayland-3.0 gtk-layer-shell-0 gmodule-export-2.0
@@ -54,8 +60,8 @@ install-bin:
 	$(INSTALL) $(NAME) $(DESTDIR)$(PREFIX)/bin/$(NAME)
 
 install-data:
-	$(INSTALL) -d $(DESTDIR)/etc/pam.d
-	$(INSTALL) -m644 pam/$(NAME) $(DESTDIR)/etc/pam.d/$(NAME)
+	$(INSTALL) -d $(DESTDIR)$(SYSCONFDIR)/pam.d
+	$(INSTALL) -m644 pam/$(NAME) $(DESTDIR)$(SYSCONFDIR)/pam.d/$(NAME)
 	$(INSTALL) -d $(DESTDIR)$(PREFIX)/share/man/man1
 	$(INSTALL) -m644 $(NAME).1 $(DESTDIR)$(PREFIX)/share/man/man1/$(NAME).1
 
@@ -63,7 +69,7 @@ install: install-bin install-data
 
 uninstall:
 	rm -f $(DESTDIR)$(PREFIX)/bin/$(NAME)
-	rm -f $(DESTDIR)/etc/pam.d/$(NAME)
+	rm -f $(DESTDIR)$(SYSCONFDIR)/pam.d/$(NAME)
 	rm -r $(DESTDIR)$(PREFIX)/share/man/man1/$(NAME).1
 
 $(NAME): $(OBJ)
diff --git a/src/source.c b/src/source.c
index 096cd63..ee3cf90 100644
--- a/src/source.c
+++ b/src/source.c
@@ -1,7 +1,7 @@
 // gtklock
 // Copyright (c) 2022 Kenny Levinsen, Jovan Lanik
 
-#define _POSIX_C_SOURCE
+#define _POSIX_C_SOURCE 200809L
 
 #include <assert.h>
 #include <signal.h>