move F_DUPFD_CLOEXEC out of bits

fcntl values 1024 and up are universal, arch-independent. later I'll
add some of the other linux-specific ones for notify, leases, pipe
size, etc. here too.
diff --git a/arch/arm/bits/fcntl.h b/arch/arm/bits/fcntl.h
index da36c2f..fc65ebc 100644
--- a/arch/arm/bits/fcntl.h
+++ b/arch/arm/bits/fcntl.h
@@ -31,5 +31,3 @@
 #define F_GETLK 12
 #define F_SETLK 13
 #define F_SETLKW 14
-
-#define F_DUPFD_CLOEXEC 1030
diff --git a/arch/i386/bits/fcntl.h b/arch/i386/bits/fcntl.h
index ab14652..7f09b95 100644
--- a/arch/i386/bits/fcntl.h
+++ b/arch/i386/bits/fcntl.h
@@ -31,5 +31,3 @@
 #define F_GETLK 12
 #define F_SETLK 13
 #define F_SETLKW 14
-
-#define F_DUPFD_CLOEXEC 1030
diff --git a/arch/x86_64/bits/fcntl.h b/arch/x86_64/bits/fcntl.h
index 40062b5..7b30021 100644
--- a/arch/x86_64/bits/fcntl.h
+++ b/arch/x86_64/bits/fcntl.h
@@ -31,5 +31,3 @@
 #define F_GETLK 5
 #define F_SETLK 6
 #define F_SETLKW 7
-
-#define F_DUPFD_CLOEXEC 1030
diff --git a/include/fcntl.h b/include/fcntl.h
index 1c18c6e..24678b2 100644
--- a/include/fcntl.h
+++ b/include/fcntl.h
@@ -34,6 +34,8 @@
 #define O_WRONLY  01
 #define O_RDWR    02
 
+#define F_DUPFD_CLOEXEC 1030
+
 #define F_RDLCK 0
 #define F_WRLCK 1
 #define F_UNLCK 2