cross/avr-libc: Update to 2.0.0nb6

Update for new avr-gcc.
MESSAGE moved to INSTALL.pkgsrc.

cross/avr-libc/Makefile

@@ -1,7 +1,7 @@
-# $NetBSD: Makefile,v 1.57 2021/08/29 20:13:41 mef Exp $
+# $NetBSD: Makefile,v 1.58 2021/09/08 12:20:35 micha Exp $
 
 DISTNAME=		avr-libc-2.0.0
-PKGREVISION=		5
+PKGREVISION=		6
 CATEGORIES=		cross
 MASTER_SITES=		http://savannah.nongnu.org/download/avr-libc/
 EXTRACT_SUFX=		.tar.bz2
@@ -21,28 +21,23 @@ CONFIGURE_ARGS+=	--disable-versioned-doc
 CONFIGURE_ARGS+=	CC=${PREFIX}/bin/avr-gcc
 CONFIGURE_ARGS+=	CPPFLAGS="-I${PREFIX}/include -I${PREFIX}/avr/include"
 
-BUILD_DEPENDS+=		doxygen>=1.8.20:../../devel/doxygen
-BUILD_DEPENDS+=		tex-hanging-[0-9]*:../../print/tex-hanging
-BUILD_DEPENDS+=		tex-stackengine-[0-9]*:../../print/tex-stackengine
-BUILD_DEPENDS+=		tex-newunicodechar-[0-9]*:../../print/tex-newunicodechar
-BUILD_DEPENDS+=		tex-etoc-[0-9]*:../../print/tex-etoc
-BUILD_DEPENDS+=		tex-epstopdf-pkg-[0-9]*:../../print/tex-epstopdf-pkg
-
-#   In doc/examples/demo directory, we have sample Makefile both for
-#   generating *.hex file at pkg installation time, and for installing
-#   Makefile itself.  That Makefile should be for general purpose, meaning
+# In share/doc/avr-libc/examples/demo directory, we have sample Makefile both
+# for generating *.hex file at pkg installation time, and for installing
+# Makefile itself. That Makefile should be for general purpose, meaning
+#
 #     OBJCOPY = avr-objcopy
-#   line should be intact. While pkg installation time it should refer
-#   wrapper ${LOCALBASE}/cross/bin files. See patch-doc_Makefile.in adding
-#   related one line.
-
+#
+# line should be intact. While pkg installation time it should refer
+# wrapper ${LOCALBASE}/cross/bin files. See patch-doc_Makefile.in adding
+# related one line.
 SUBST_CLASSES+=		demo
 SUBST_STAGE.demo=	pre-configure
 SUBST_MESSAGE.demo=	Add cross/bin on PATH for OBJCOPY (avr-objcopy) etc
 SUBST_FILES.demo=	doc/Makefile.in
 SUBST_SED.demo=		-e 's|@@@PATH@@@|${PREFIX}/bin:${PATH:Q}|g'
 
 .include "options.mk"
+
 .include "../../cross/avr-binutils/buildlink3.mk"
 .include "../../cross/avr-gcc/buildlink3.mk"
 .include "../../mk/bsd.pkg.mk"