add defines for number of sigset_t bytes syscalls expect

yet another gratuitous mips incompatibility...
diff --git a/arch/arm/bits/syscall.h b/arch/arm/bits/syscall.h
index 816d7b0..9932c9e 100644
--- a/arch/arm/bits/syscall.h
+++ b/arch/arm/bits/syscall.h
@@ -3,6 +3,8 @@
 ((union { long long ll; long l[2]; }){ .ll = x }).l[1]
 #define __SYSCALL_LL_O(x) 0, __SYSCALL_LL_E((x))
 
+#define __SYSCALL_SSLEN 8
+
 long (__syscall)(long, ...);
 
 static inline long __syscall0(long n)
diff --git a/arch/i386/bits/syscall.h b/arch/i386/bits/syscall.h
index 37b339c..4b574e9 100644
--- a/arch/i386/bits/syscall.h
+++ b/arch/i386/bits/syscall.h
@@ -3,6 +3,8 @@
 ((union { long long ll; long l[2]; }){ .ll = x }).l[1]
 #define __SYSCALL_LL_O(x) __SYSCALL_LL_E((x))
 
+#define __SYSCALL_SSLEN 8
+
 static inline long __syscall0(long __n)
 {
 	unsigned long __ret;
diff --git a/arch/mips/bits/syscall.h b/arch/mips/bits/syscall.h
index 868ce0f..6c51bab 100644
--- a/arch/mips/bits/syscall.h
+++ b/arch/mips/bits/syscall.h
@@ -3,6 +3,8 @@
 ((union { long long ll; long l[2]; }){ .ll = x }).l[1]
 #define __SYSCALL_LL_O(x) 0, __SYSCALL_LL_E((x))
 
+#define __SYSCALL_SSLEN 16
+
 long (__syscall)(long, ...);
 
 static inline long __syscall0(long n)
diff --git a/arch/x86_64/bits/syscall.h b/arch/x86_64/bits/syscall.h
index 61a67a7..567cfcb 100644
--- a/arch/x86_64/bits/syscall.h
+++ b/arch/x86_64/bits/syscall.h
@@ -1,6 +1,8 @@
 #define __SYSCALL_LL_E(x) (x)
 #define __SYSCALL_LL_O(x) (x)
 
+#define __SYSCALL_SSLEN 8
+
 static inline long __syscall0(long __n)
 {
 	unsigned long __ret;