Work around conflict between <sys/ptrace.h> and <linux/ptrace.h>

Since glibc-2.18~39 <sys/ptrace.h> defines ptrace_peeksiginfo_args
which collides with <linux/ptrace.h>.

* configure.ac: Check for `struct ptrace_peeksiginfo_args' in
<sys/ptrace.h>.
* process.c: Work around potential conflict between <sys/ptrace.h>
and <linux/ptrace.h> by redefining ptrace_peeksiginfo_args.
* signal.c: Likewise.
* syscall.c: Likewise.
* util.c: Likewise.

Signed-off-by: Ali Polatel <alip@exherbo.org>
diff --git a/syscall.c b/syscall.c
index 83a95bd..3477dcd 100644
--- a/syscall.c
+++ b/syscall.c
@@ -48,7 +48,11 @@
 # ifdef HAVE_STRUCT_PT_ALL_USER_REGS
 #  define pt_all_user_regs XXX_pt_all_user_regs
 # endif
+# ifdef HAVE_STRUCT_PTRACE_PEEKSIGINFO_ARGS
+#  define ptrace_peeksiginfo_args XXX_ptrace_peeksiginfo_args
+# endif
 # include <linux/ptrace.h>
+# undef ptrace_peeksiginfo_args
 # undef ia64_fpreg
 # undef pt_all_user_regs
 #endif