sys/time.h: include time.h

Due to a Meson annoyance explained in a comment in sys/time.h, #include
<time.h> from sys/time.h.

meson.build

@@ -104,6 +104,9 @@ libobsd = library('obsd', src,
                   c_args: args,
                   install: not subproj,
                   include_directories: incdir,
+                  # To prevent Meson from making the compiler confuse sys/time.h
+                  # with time.h
+                  implicit_include_directories: false,
                   dependencies: deps,
                   gnu_symbol_visibility: 'hidden',
                   override_options: link)

src/time/sys/time.h.in

@@ -47,6 +47,16 @@
 #if !defined(OBSD_H_TIME)
 #define OBSD_H_TIME
 
+/* Meson adds libobsd/src/time/sys to the include path and there's no way to
+ * remove it, which means someone might try to include time.h and end up being
+ * satisfied by sys/time.h. This will probably cause errors over missing types
+ * later (it does on HaikuOS, doesn't seem to on others), so make sure the right
+ * time.h is also included.
+ */
+#if defined(__HAIKU__)
+	#include <../posix/time.h>
+#endif
+
 #include <obsd_defs.h>
 #pragma obsd sys_time.h #define OBSD_INC_NEXT sys/time.h
 #pragma obsd sys_time.h #include <obsd_inc_next.h>