dlopen: add support for INPUT(-lXXX)

GitHub: fix GH-166

Arch Linux's libncurses.so uses this style.

Author: kou

lib/fiddle.rb

@@ -111,7 +111,11 @@ def dlopen library
           case line
           when /\A\s*(?:INPUT|GROUP)\s*\(\s*([^\s,\)]+)/
             # TODO: Should we support multiple files?
-            return dlopen($1)
+            first_input = $1
+            if first_input.start_with?("-l")
+              first_input = "lib#{first_input[2..-1]}.so"
+            end
+            return dlopen(first_input)
           end
         end
       end

test/fiddle/test_fiddle.rb

@@ -34,13 +34,34 @@ def test_dlopen_linker_script_input_linux
       omit("Fiddle::Handle#file_name doesn't exist in FFI backend")
     end
 
-    # libncurses.so uses INPUT() on Debian GNU/Linux
+    # libncurses.so uses INPUT() on Debian GNU/Linux and Arch Linux:
+    #
+    # Debian GNU/Linux:
+    #
     # $ cat /usr/lib/x86_64-linux-gnu/libncurses.so
     # INPUT(libncurses.so.6 -ltinfo)
+    #
+    # Arch Linux:
+    # $ cat /usr/lib/libncurses.so
+    # INPUT(-lncursesw)
     handle = Fiddle.dlopen("libncurses.so")
     begin
-      assert_equal("libncurses.so",
-                   File.basename(handle.file_name, ".*"))
+      # /usr/lib/x86_64-linux-gnu/libncurses.so.6 ->
+      # libncurses.so.6
+      normalized_file_name = File.basename(handle.file_name)
+      # libncurses.so.6 ->
+      # libncurses.so
+      #
+      # libncursesw.so ->
+      # libncursesw.so
+      normalized_file_name = normalized_file_name.sub(/\.so(\.\d+)+\z/, ".so")
+      # libncurses.so ->
+      # libncurses.so
+      #
+      # libncursesw.so ->
+      # libncurses.so
+      normalized_file_name = normalized_file_name.sub(/ncursesw/, "ncurses")
+      assert_equal("libncurses.so", normalized_file_name)
     ensure
       handle.close
     end