Fix macOS build target in Xcode project.

- Add missing files for desktop platforms in generate-darwin-source-and-headers.py, and in the Xcode project.
- Add a static library target for macOS.
- Fix "implicit conversion loses integer precision" warnings for iOS mad macOS targets.

src/aarch64/ffi.c

@@ -231,7 +231,7 @@ is_vfp_type (const ffi_type *ty)
 
   /* All tests succeeded.  Encode the result.  */
  done:
-  return candidate * 4 + (4 - ele_count);
+  return candidate * 4 + (4 - (int)ele_count);
 }
 
 /* Representation of the procedure call argument marshalling
@@ -528,7 +528,7 @@ ffi_prep_cif_machdep (ffi_cif *cif)
       }
 
   /* Round the stack up to a multiple of the stack alignment requirement. */
-  cif->bytes = ALIGN(bytes, 16);
+  cif->bytes = (unsigned) ALIGN(bytes, 16);
   cif->flags = flags;
 #if defined (__APPLE__)
   cif->aarch64_nfixedargs = 0;

src/closures.c

@@ -506,7 +506,7 @@ open_temp_exec_file_dir (const char *dir)
   }
 #endif
 
-  lendir = strlen (dir);
+  lendir = (int) strlen (dir);
   tempname = __builtin_alloca (lendir + sizeof (suffix));
 
   if (!tempname)

src/x86/ffi64.c

@@ -395,7 +395,8 @@ ffi_prep_cif_machdep_efi64(ffi_cif *cif);
 ffi_status
 ffi_prep_cif_machdep (ffi_cif *cif)
 {
-  int gprcount, ssecount, i, avn, ngpr, nsse, flags;
+  int gprcount, ssecount, i, avn, ngpr, nsse;
+  unsigned flags;
   enum x86_64_reg_class classes[MAX_CLASSES];
   size_t bytes, n, rtype_size;
   ffi_type *rtype;
@@ -494,7 +495,7 @@ ffi_prep_cif_machdep (ffi_cif *cif)
 	case FFI_TYPE_SINT32:
 	case FFI_TYPE_UINT64:
 	case FFI_TYPE_SINT64:
-	  flags = UNIX64_RET_ST_RAX_RDX | (rtype_size << UNIX64_SIZE_SHIFT);
+	  flags = UNIX64_RET_ST_RAX_RDX | ((unsigned) rtype_size << UNIX64_SIZE_SHIFT);
 	  break;
 	case FFI_TYPE_FLOAT:
 	  flags = UNIX64_RET_XMM64;
@@ -542,7 +543,7 @@ ffi_prep_cif_machdep (ffi_cif *cif)
     flags |= UNIX64_FLAG_XMM_ARGS;
 
   cif->flags = flags;
-  cif->bytes = ALIGN (bytes, 8);
+  cif->bytes = (unsigned) ALIGN (bytes, 8);
 
   return FFI_OK;
 }