media-libs/libnjb: fixed doc installation path

Closes: https://bugs.gentoo.org/854813
Signed-off-by: Miroslav Šulc <fordfrog@gentoo.org>

media-libs/libnjb/files/libnjb-2.2.7-fix-docdir.patch

@@ -0,0 +1,13 @@
+diff --git a/doc/Makefile.in b/doc/Makefile.in
+index 5a9b1bb..3e25fb5 100644
+--- a/doc/Makefile.in
++++ b/doc/Makefile.in
+@@ -169,7 +169,7 @@ top_build_prefix = @top_build_prefix@
+ top_builddir = @top_builddir@
+ top_srcdir = @top_srcdir@
+ EXTRA_DIST = Doxyfile.in examples.h mainpage.h
+-@HAVE_DOXYGEN_TRUE@pkgdocdir = $(datadir)/doc/$(PACKAGE)-$(VERSION)
++@HAVE_DOXYGEN_TRUE@pkgdocdir = $(docdir)
+ @HAVE_DOXYGEN_TRUE@htmldocdir = $(pkgdocdir)/html
+ all: all-am
+ 

media-libs/libnjb/libnjb-2.2.7-r2.ebuild

@@ -18,7 +18,10 @@ RDEPEND="virtual/libusb:0"
 DEPEND="${RDEPEND}
 	doc? ( app-doc/doxygen )"
 
-PATCHES=( "${FILESDIR}"/${P}-exclude-samples.patch )
+PATCHES=(
+	"${FILESDIR}"/${P}-exclude-samples.patch
+	"${FILESDIR}"/${P}-fix-docdir.patch
+)
 
 src_prepare() {
 	default