doc,win32: update note on which files to use with shared libraries in msvc

Originally committed as revision 25365 to svn://svn.ffmpeg.org/ffmpeg/trunk

doc/general.texi

@@ -978,9 +978,12 @@ To use those files with MSVC++, do the same as you would do with
 the static libraries, as described above. But in Step 4,
 you should only need to add the directory where the LIB files are installed
 (i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
-installed in the @file{bin} directory. And instead of adding @file{libxx.a}
-files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
-@file{avutil.lib}. There should be no need for @file{libmingwex.a},
+installed in the @file{bin} directory. And instead of adding the static
+libraries (@file{libxxx.a} files) you should add the MSVC import libraries
+(@file{avcodec.lib}, @file{avformat.lib}, @file{avcore.lib}, and
+@file{avutil.lib}). Note that you should not use the GCC import
+libraries (@file{libxxx.dll.a} files), as these will give you undefined
+reference errors. There should be no need for @file{libmingwex.a},
 @file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
 statically linked into the DLLs. The @file{bin} directory contains a bunch
 of DLL files, but the ones that are actually used to run your application