Win32: support 64-bit compilation with MSVC.

There are lots of C4244 warnings (conversion from 'type1' to 'type2',
possible loss of data), so they were disabled.

The same applies to C4267 warnings (conversion from 'size_t' to 'type',
possible loss of data), most notably - conversion from ngx_str_t.len to
ngx_variable_value_t.len (which is unsigned:28).  Additionally, there
is at least one case when it is not possible to fix the warning properly
without introducing win32-specific code: recv() on win32 uses "int len",
while POSIX defines "size_t len".

The ssize_t type now properly defined for 64-bit compilation with MSVC.
Caught by warning C4305 (truncation from '__int64' to 'ssize_t'), on
"cutoff = NGX_MAX_SIZE_T_VALUE / 10" in ngx_atosz()).

Several C4334 warnings (result of 32-bit shift implicitly converted to 64 bits)
were fixed by adding explicit conversions.

Several C4214 warnings (nonstandard extension used: bit field types other
than int) in ngx_http_script.h fixed by changing bit field types from
uintptr_t to unsigned.

src/core/ngx_slab.c

@@ -101,7 +101,7 @@ ngx_slab_init(ngx_slab_pool_t *pool)
     }
     /**/
 
-    pool->min_size = 1 << pool->min_shift;
+    pool->min_size = (size_t) 1 << pool->min_shift;
 
     slots = ngx_slab_slots(pool);
 
@@ -473,7 +473,7 @@ ngx_slab_free_locked(ngx_slab_pool_t *pool, void *p)
     case NGX_SLAB_SMALL:
 
         shift = slab & NGX_SLAB_SHIFT_MASK;
-        size = 1 << shift;
+        size = (size_t) 1 << shift;
 
         if ((uintptr_t) p & (size - 1)) {
             goto wrong_chunk;
@@ -568,7 +568,7 @@ ngx_slab_free_locked(ngx_slab_pool_t *pool, void *p)
     case NGX_SLAB_BIG:
 
         shift = slab & NGX_SLAB_SHIFT_MASK;
-        size = 1 << shift;
+        size = (size_t) 1 << shift;
 
         if ((uintptr_t) p & (size - 1)) {
             goto wrong_chunk;

src/http/ngx_http_script.c

@@ -356,11 +356,11 @@ ngx_http_script_compile(ngx_http_script_compile_t *sc)
 
                 n = sc->source->data[i] - '0';
 
-                if (sc->captures_mask & (1 << n)) {
+                if (sc->captures_mask & ((ngx_uint_t) 1 << n)) {
                     sc->dup_capture = 1;
                 }
 
-                sc->captures_mask |= 1 << n;
+                sc->captures_mask |= (ngx_uint_t) 1 << n;
 
                 if (ngx_http_script_add_capture_code(sc, n) != NGX_OK) {
                     return NGX_ERROR;

src/http/ngx_http_script.h

@@ -121,16 +121,16 @@ typedef struct {
     uintptr_t                   status;
     uintptr_t                   next;
 
-    uintptr_t                   test:1;
-    uintptr_t                   negative_test:1;
-    uintptr_t                   uri:1;
-    uintptr_t                   args:1;
+    unsigned                    test:1;
+    unsigned                    negative_test:1;
+    unsigned                    uri:1;
+    unsigned                    args:1;
 
     /* add the r->args to the new arguments */
-    uintptr_t                   add_args:1;
+    unsigned                    add_args:1;
 
-    uintptr_t                   redirect:1;
-    uintptr_t                   break_cycle:1;
+    unsigned                    redirect:1;
+    unsigned                    break_cycle:1;
 
     ngx_str_t                   name;
 } ngx_http_script_regex_code_t;
@@ -139,13 +139,13 @@ typedef struct {
 typedef struct {
     ngx_http_script_code_pt     code;
 
-    uintptr_t                   uri:1;
-    uintptr_t                   args:1;
+    unsigned                    uri:1;
+    unsigned                    args:1;
 
     /* add the r->args to the new arguments */
-    uintptr_t                   add_args:1;
+    unsigned                    add_args:1;
 
-    uintptr_t                   redirect:1;
+    unsigned                    redirect:1;
 } ngx_http_script_regex_end_code_t;
 
 #endif

src/os/win32/ngx_win32_config.h

@@ -94,6 +94,12 @@ typedef long  time_t;
 /* FD_SET() and FD_CLR(): conditional expression is constant */
 #pragma warning(disable:4127)
 
+/* conversion from 'type1' to 'type2', possible loss of data */
+#pragma warning(disable:4244)
+
+/* conversion from 'size_t' to 'type', possible loss of data */
+#pragma warning(disable:4267)
+
 /* array is too small to include a terminating null character */
 #pragma warning(disable:4295)
 
@@ -189,8 +195,12 @@ typedef unsigned int        ino_t;
 
 
 #ifndef __GNUC__
+#ifdef _WIN64
+typedef __int64             ssize_t;
+#else
 typedef int                 ssize_t;
 #endif
+#endif
 
 
 typedef uint32_t            in_addr_t;