Code replicated in compression and decompression moved to shared headers
`CHECK_F` macro moved to `error_private.h` (shared between `fse_compress.c` and `fse_decompress.c`). `ZSTD_limitCopy()` moved to `zstd_internal.h` (shared between `zstd_compress.c` and `zstd_decompress.c`). Erroneous build artefact `zstd.h` removed from repo.
diff --git a/lib/common/error_private.h b/lib/common/error_private.h
index 78a9780..ced1a3b 100644
--- a/lib/common/error_private.h
+++ b/lib/common/error_private.h
@@ -57,6 +57,10 @@
ERR_STATIC ERR_enum ERR_getErrorCode(size_t code) { if (!ERR_isError(code)) return (ERR_enum)0; return (ERR_enum) (0-code); }
+/* check and forward error code */
+#define CHECK_V_F(e, f) size_t const e = f; if (ERR_isError(e)) return e
+#define CHECK_F(f) { CHECK_V_F(_var_err__, f); }
+
/*-****************************************
* Error Strings