Merge pull request #3401 from andralex/odbc-instructions

Add ODBC linking instructions

etc/c/odbc/sql.d

@@ -10,6 +10,14 @@ original announcement)).
 corresponding to the `sql.h` C header file. It `import`s `public`ly
 `etc.c.odbc.sqltypes` for conformity with the C header.
 
+Note: The ODBC library itself not a part of the `dmd` distribution (and
+typically not a part of the distribution packages of other compilers
+such as `gdc` and `ldc`). To use ODBC, install it per the vendor- and
+platform-specific instructions and then use the appropriate command-line
+flags (e.g. for dmd, `-L-lodbc` on Posix and `-Lodbc32.lib` on Windows) to link
+with the ODBC library. On Windows, using $(D pragma(lib, "odbc32")) in D
+code at top level is also appropriate.
+
 See_Also: $(LUCKY ODBC API Reference on MSN Online)
 */