diff --git a/arguments.c b/arguments.c
index 05ff97eb..ca6cc760 100644
--- a/arguments.c
+++ b/arguments.c
@@ -18,7 +18,6 @@
 
 #include <sys/types.h>
 
-#include <getopt.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
diff --git a/configure.ac b/configure.ac
index 24aded53..de336fef 100644
--- a/configure.ac
+++ b/configure.ac
@@ -96,6 +96,9 @@ AC_CHECK_HEADERS(
 	]
 )
 
+# Look for library needed for flock.
+AC_SEARCH_LIBS(flock, bsd)
+
 # Check for some functions that are replaced or omitted.
 AC_CHECK_FUNCS(
 	[ \
diff --git a/tmux.c b/tmux.c
index 62f8a808..39f344c0 100644
--- a/tmux.c
+++ b/tmux.c
@@ -22,7 +22,6 @@
 #include <errno.h>
 #include <event.h>
 #include <fcntl.h>
-#include <getopt.h>
 #include <locale.h>
 #include <pwd.h>
 #include <stdlib.h>