main/ruby: patch Rubygems to avoid fetching platform-specific gems

For more information see description in the patch file.

main/ruby/APKBUILD

@@ -4,7 +4,7 @@
 pkgname=ruby
 pkgver=2.4.1
 _abiver="${pkgver%.*}.0"
-pkgrel=2
+pkgrel=3
 pkgdesc="An object-oriented language for quick and easy programming"
 url="http://www.ruby-lang.org/en/"
 arch="all"
@@ -28,7 +28,8 @@ subpackages="$pkgname-doc $pkgname-dev
 	$pkgname-xmlrpc::noarch
 	$pkgname-libs
 	"
-source="ftp://ftp.ruby-lang.org/pub/ruby/${pkgver%.*}/$pkgname-$pkgver.tar.bz2"
+source="ftp://ftp.ruby-lang.org/pub/ruby/${pkgver%.*}/$pkgname-$pkgver.tar.bz2
+	rubygems-avoid-platform-specific-gems.patch"
 options="!fhs"
 replaces="ruby-gems"
 builddir="$srcdir/$pkgname-$pkgver"
@@ -225,4 +226,5 @@ _mvgem() {
 	done
 }
 
-sha512sums="1c80d4c30ecb51758a193b26b76802a06d214de7f15570f1e85b5fae4cec81bda7237f086b81f6f2b5767f2e93d347ad1fa3f49d7b5c2e084d5f57c419503f74  ruby-2.4.1.tar.bz2"
+sha512sums="1c80d4c30ecb51758a193b26b76802a06d214de7f15570f1e85b5fae4cec81bda7237f086b81f6f2b5767f2e93d347ad1fa3f49d7b5c2e084d5f57c419503f74  ruby-2.4.1.tar.bz2
+cfdc5ea3b2e2ea69c51f38e8e2180cb1dc27008ca55cc6301f142ebafdbab31c3379b3b6bba9ff543153876dd98ed2ad194df3255b7ea77a62e931c935f80538  rubygems-avoid-platform-specific-gems.patch"

main/ruby/rubygems-avoid-platform-specific-gems.patch

+From: Jakub Jirutka <jakub@jirutka.cz>
+Date: Fri, 19 May 2017 19:56:00 +0200
+Subject: [PATCH] Rubygems: don't install platform-specific gems
+
+Gems with native extensions typically contain just source code that is
+built during installation on user's system. However, Rubygems allows to
+publish even platform-specific gems with prebuilt binaries for specific
+platform. The problem is that Rubygems uses only short platform
+identification like x86_64-linux; it does not identify used libc.
+And sadly platform-specific gems for linux are built against glibc, so
+they may not work on musl libc.
+
+This patch is a workaround for the aforesaid problem. It removes local
+platform from Rubygems' supported platforms to force it always pick
+a platform-agnostic (source) gem. Users can override it using
+`--platform` option.
+
+--- a/lib/rubygems.rb
++++ b/lib/rubygems.rb
+@@ -743,7 +743,10 @@
+   def self.platforms
+     @platforms ||= []
+     if @platforms.empty?
+-      @platforms = [Gem::Platform::RUBY, Gem::Platform.local]
++      # XXX: Patched to avoid installing platform-specific gems with binaries
++      # linked against glibc.
++      @platforms = [Gem::Platform::RUBY]
++      #@platforms = [Gem::Platform::RUBY, Gem::Platform.local]
+     end
+     @platforms
+   end