dev-python/pillow: fix link warnings

Apply patch to remove spurious /usr/lib prepend to linking flags that
generates linking warnings in certain situations.

Reported-By: Alexander Tsoy
Closes: https://bugs.gentoo.org/661830
Package-Manager: Portage-2.3.43, Repoman-2.3.10

dev-python/pillow/files/pillow-5.2.0-no-usr-lib.patch

@@ -0,0 +1,12 @@
+--- a/setup.py	2018-07-22 22:09:23.840195059 +0300
++++ a/setup.py	2018-07-22 22:11:43.400626135 +0300
+@@ -258,9 +258,8 @@ 
+                     _add_directory(library_dirs, d)
+ 
+         prefix = sysconfig.get_config_var("prefix")
+         if prefix:
+-            _add_directory(library_dirs, os.path.join(prefix, "lib"))
+             _add_directory(include_dirs, os.path.join(prefix, "include"))
+ 
+         #
+         # add platform directories

dev-python/pillow/pillow-5.2.0.ebuild

@@ -46,6 +46,10 @@ DEPEND="${RDEPEND}
 
 S="${WORKDIR}/${MY_P}"
 
+PATCHES=(
+	"${FILESDIR}/${PN}-5.2.0-no-usr-lib.patch"
+)
+
 python_configure_all() {
 	# It's important that these flags are also passed during the install phase
 	# as well. Make sure of that if you change the lines below. See bug 661308.