Fix windows compilation warnings

Fix some warnings in the async code when compiling on windows.

Reviewed-by: Rich Salz <rsalz@openssl.org>

crypto/async/arch/async_null.c

@@ -91,5 +91,20 @@ int async_pool_can_grow(void) {
     return 0;
 }
 
+int async_pipe(int *pipefds)
+{
+    return -1;
+}
+
+int async_write1(int fd, const void *buf)
+{
+    return -1;
+}
+
+int async_read1(int fd, void *buf)
+{
+    return -1;
+}
+
 #endif
 

crypto/async/arch/async_null.h

@@ -73,8 +73,5 @@ typedef struct async_fibre_st {
 # define ASYNC_FIBRE_makecontext(c)
 # define ASYNC_FIBRE_free(f)
 # define ASYNC_FIBRE_init_dispatcher(f)
-# define async_pipe(f)                          0
-# define async_write1(f,b)                      ((*b == 0) ? (f = 0) : (f = 1))
-# define async_read1(f,b)                       (*b = 0)
 
 #endif

crypto/async/arch/async_posix.h

@@ -99,9 +99,5 @@ static inline int ASYNC_FIBRE_swapcontext(ASYNC_FIBRE *o, ASYNC_FIBRE *n, int r)
 int ASYNC_FIBRE_init(ASYNC_FIBRE *fibre);
 void ASYNC_FIBRE_free(ASYNC_FIBRE *fibre);
 
-int async_pipe(int *pipefds);
-int async_write1(int fd, const void *buf);
-int async_read1(int fd, void *buf);
-
 # endif
 #endif

crypto/async/async_locl.h

@@ -87,3 +87,6 @@ void async_release_job_to_pool(ASYNC_JOB *job);
 size_t async_pool_max_size(void);
 void async_release_pool(void);
 int async_pool_can_grow(void);
+int async_pipe(int *pipefds);
+int async_write1(int fd, const void *buf);
+int async_read1(int fd, void *buf);