[hurd,commited] hurd: avoid including hurd/signal.h when not needed

[Samuel Thibault <samuel dot thibault at ens-lyon dot org>]

thus making <hurd/port.h> and <hurd/userlink.h> includable without
_GNU_SOURCE.

	* hurd/hurd/port.h: Do not include <hurd/signal.h>.
	* hurd/hurd/userlink.h [!defined __USE_EXTERN_INLINES ||
	!defined _LIBC || !IS_IN (libc)]: Do not include <hurd/signal.h>.
---
 ChangeLog            | 3 +++
 hurd/hurd/port.h     | 1 -
 hurd/hurd/userlink.h | 6 +++++-
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 9bfa1bd316..297af745e2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -11,6 +11,9 @@
 	* sysdeps/mach/i386/bits/mach/param.h: ... here.  Update path in #error.
 	* sysdeps/mach/hurd/bits/param.h: Include <bits/mach/param.h> instead
 	of <mach/param.h>.
+	* hurd/hurd/port.h: Do not include <hurd/signal.h>.
+	* hurd/hurd/userlink.h [!defined __USE_EXTERN_INLINES ||
+	!defined _LIBC || !IS_IN (libc)]: Do not include <hurd/signal.h>.
 
 2018-03-03  Andreas Schwab  <schwab@linux-m68k.org>
 
diff --git a/hurd/hurd/port.h b/hurd/hurd/port.h
index eec85ccc29..0779578d03 100644
--- a/hurd/hurd/port.h
+++ b/hurd/hurd/port.h
@@ -24,7 +24,6 @@
 #include <mach.h>
 #include <hurd/userlink.h>
 #include <spin-lock.h>
-#include <hurd/signal.h>
 
 
 /* Structure describing a cell containing a port.  With the lock held, a
diff --git a/hurd/hurd/userlink.h b/hurd/hurd/userlink.h
index fb7cab27c3..f9362557cb 100644
--- a/hurd/hurd/userlink.h
+++ b/hurd/hurd/userlink.h
@@ -24,7 +24,11 @@
 #define __need_NULL
 #include <stddef.h>
 
-#include <hurd/signal.h>
+#if defined __USE_EXTERN_INLINES && defined _LIBC
+# if IS_IN (libc)
+#  include <hurd/signal.h>
+# endif
+#endif
 #include <setjmp.h>
 
 
-- 
2.16.1