move bits/signal.h include close to the top of signal.h

only have code above the bits/signal.h include that is necessary.
(some types are used for the ucontext struct and mips has to
override a few macro definitions)

this way mips bits/signal.h will be able to affect siginfo_t.

include/signal.h

@@ -27,8 +27,6 @@ extern "C" {
 
 #include <bits/alltypes.h>
 
-#define SIG_HOLD ((void (*)(int)) 2)
-
 #define SIG_BLOCK     0
 #define SIG_UNBLOCK   1
 #define SIG_SETMASK   2
@@ -43,6 +41,18 @@ extern "C" {
 #define SI_USER 0
 #define SI_KERNEL 128
 
+typedef struct sigaltstack stack_t;
+
+#endif
+
+#include <bits/signal.h>
+
+#if defined(_POSIX_SOURCE) || defined(_POSIX_C_SOURCE) \
+ || defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) \
+ || defined(_BSD_SOURCE)
+
+#define SIG_HOLD ((void (*)(int)) 2)
+
 #define FPE_INTDIV 1
 #define FPE_INTOVF 2
 #define FPE_FLTDIV 3
@@ -78,8 +88,6 @@ extern "C" {
 #define CLD_STOPPED 5
 #define CLD_CONTINUED 6
 
-typedef struct sigaltstack stack_t;
-
 union sigval {
 	int sival_int;
 	void *sival_ptr;
@@ -240,8 +248,6 @@ int sigandset(sigset_t *, const sigset_t *, const sigset_t *);
 #define SA_ONESHOT SA_RESETHAND
 #endif
 
-#include <bits/signal.h>
-
 #define SIG_ERR  ((void (*)(int))-1)
 #define SIG_DFL  ((void (*)(int)) 0)
 #define SIG_IGN  ((void (*)(int)) 1)