-(see <xref linkend="ghc-mingw">).
-
-Both these options are important! It's possible to get into
-trouble using the wrong C compiler!</para>
+(see <xref linkend="ghc-mingw">). </para>
+
+<para> Both these options are important! It's possible to get into
+trouble using the wrong C compiler!
+Furthermore, it's very important that you specify a
+full mingw path for <command>gcc</command>, not a cygwin path, because GHC (which
+uses this path to invoke <command>gcc</command>) is a Mingw program and won't
+understand a cygwin path.. For example, if you
+say <literal>--with-gcc=/mingw/bin/gcc</literal>, it'll be interpreted as
+<filename>/cygdrive/c/mingw/bin/gcc</filename>, and GHC will fail the first
+time it tries to invoke it. (Worse, the failure does not come with
+a helpful error message, unfortunately.)
+</para>