doxygen: update recipe

* Remove libiconv from BUILD_PREREQUIRES. Add lib:libiconv to
  REQUIRES and devel:libiconv to BUILD_REQUIRES instead.
* REQUIRES: haiku_devel -> haiku

app-doc/doxygen/doxygen-1.6.3.recipe

@@ -11,7 +11,7 @@ COPYRIGHT="1997-2010 Dimitri van Heesch"
 LICENSE="GNU GPL v2"
 SRC_URI="http://ftp.stack.nl/pub/users/dimitri/doxygen-1.6.3.src.tar.gz"
 CHECKSUM_MD5="2d6ea20a9d850d94321cee78bab7bb87"
-REVISION="2"
+REVISION="3"
 ARCHITECTURES="x86_gcc2 ?x86"
 
 PATCHES="doxygen-1.6.3.patch"
@@ -22,14 +22,14 @@ PROVIDES="
 	cmd:doxytag = $portVersion compat >= 1.6
 	"
 REQUIRES="
-	haiku_devel >= $haikuVersion
+	haiku >= $haikuVersion
+	lib:libiconv
 	"
 BUILD_REQUIRES="
-	$REQUIRES
+	devel:libiconv
 	"
 BUILD_PREREQUIRES="
 	haiku_devel >= $haikuVersion
-	libiconv
 	cmd:bison
 	cmd:flex
 	cmd:gcc