Fixes various warnings noticed on Windows (#425)

* Fixes various warnings noticed on Windows

- Adds a prototype for our implementation of vasprintf
- Return type of H5_get_utf16_str() is now non-const
- Fixes possible uninitialized return type in Wremove_utf8
- Better isolation of fork() code in accum.c:test_swmr_write_big()
- Better isolation of non-zlib code in dsets.c:test_filter_delete()
- Removed unused variable in trefer.c:test_reference_cmpnd_obj()

* Fixes clang-format issues

1 files changed, 7 insertions, 3 deletions

diff --git a/test/dsets.c b/test/dsets.c
index 5dcdbce..8600d75 100644
--- a/test/dsets.c
+++ b/test/dsets.c
@@ -6976,6 +6976,7 @@ error:
 static herr_t
 test_filter_delete(hid_t file)
 {
+#ifdef H5_HAVE_FILTER_DEFLATE
     H5Z_filter_t filtn;                    /* filter identification number */
     hid_t        dsid          = -1;       /* dataset ID */
     hid_t        sid           = -1;       /* dataspace ID */
@@ -6987,6 +6988,7 @@ test_filter_delete(hid_t file)
     unsigned     flags;                    /* flags for filter */
     herr_t       ret;                      /* generic return value */
     int          i;
+#endif
 
     TESTING("filter deletion");
 
@@ -7088,9 +7090,7 @@ test_filter_delete(hid_t file)
         goto error;
 
     PASSED();
-#else
-    SKIPPED();
-#endif
+
     return SUCCEED;
 
 error:
@@ -7103,6 +7103,10 @@ error:
     }
     H5E_END_TRY;
     return FAIL;
+#else
+    SKIPPED();
+    return SUCCEED;
+#endif
 } /* end test_filter_delete() */
 
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