Ensure that PTRACE_GETSIGINFO et al are always defined on Linux

* configure.ac (AC_CHECK_DECLS): Add PTRACE_* constants.
* defs.h [LINUX]: Define those PTRACE_* constants that are not provided
by <sys/ptrace.h>.

configure.ac

@@ -306,6 +306,16 @@ AC_CHECK_MEMBERS([struct sigcontext.sc_hi2],,, [#include <signal.h>
 
 AC_CHECK_DECLS([sys_errlist])
 AC_CHECK_DECLS([sys_siglist, _sys_siglist],,, [#include <signal.h>])
+AC_CHECK_DECLS([\
+		PTRACE_SETOPTIONS, \
+		PTRACE_GETEVENTMSG, \
+		PTRACE_GETSIGINFO, \
+		PTRACE_O_TRACEFORK, \
+		PTRACE_O_TRACEVFORK, \
+		PTRACE_O_TRACECLONE, \
+		PTRACE_EVENT_FORK, \
+		PTRACE_EVENT_VFORK, \
+		PTRACE_EVENT_CLONE],,, [#include <sys/ptrace.h>])
 
 AC_PATH_PROG([PERL], [perl])
 

defs.h

@@ -309,29 +309,32 @@ extern int mp_ioctl (int f, int c, void *a, int s);
 #endif
 
 #ifdef LINUX
-# ifndef PTRACE_SETOPTIONS
+# if !HAVE_DECL_PTRACE_SETOPTIONS
 #  define PTRACE_SETOPTIONS	0x4200
 # endif
-# ifndef PTRACE_GETEVENTMSG
+# if !HAVE_DECL_PTRACE_GETEVENTMSG
 #  define PTRACE_GETEVENTMSG	0x4201
 # endif
-# ifndef PTRACE_O_TRACEFORK
+# if !HAVE_DECL_PTRACE_GETSIGINFO
+#  define PTRACE_GETSIGINFO	0x4202
+# endif
+# if !HAVE_DECL_PTRACE_O_TRACEFORK
 #  define PTRACE_O_TRACEFORK	0x00000002
 # endif
-# ifndef PTRACE_O_TRACEVFORK
+# if !HAVE_DECL_PTRACE_O_TRACEVFORK
 #  define PTRACE_O_TRACEVFORK	0x00000004
 # endif
-# ifndef PTRACE_O_TRACECLONE
+# if !HAVE_DECL_PTRACE_O_TRACECLONE
 #  define PTRACE_O_TRACECLONE	0x00000008
 # endif
 
-# ifndef PTRACE_EVENT_FORK
+# if !HAVE_DECL_PTRACE_EVENT_FORK
 #  define PTRACE_EVENT_FORK	1
 # endif
-# ifndef PTRACE_EVENT_VFORK
+# if !HAVE_DECL_PTRACE_EVENT_VFORK
 #  define PTRACE_EVENT_VFORK	2
 # endif
-# ifndef PTRACE_EVENT_CLONE
+# if !HAVE_DECL_PTRACE_EVENT_CLONE
 #  define PTRACE_EVENT_CLONE	3
 # endif
 #endif /* LINUX */