fix: add the recipe lib path to $LDFLAGS

This probably should have always been the behavior. This works around
the behavior of Fedora's pkgconf described in #118.

I'm a little worried that this might break packages in some subtle
way, so the `set_ldflags` option will turn it off if needed.

examples/Rakefile

@@ -1,9 +1,9 @@
 require 'rbconfig'
-require 'mkmf'
 
 $: << File.expand_path(File.join(File.dirname(__FILE__), "../lib"))
 require "mini_portile2"
 
+$LDFLAGS = "-mimic-being-in-extconf" # mimic being in an extconf (mkmf.rb sets this global variable)
 recipes = []
 recipe_hooks = {}
 
@@ -132,11 +132,6 @@ yaml.files = [{
 recipes.push(yaml)
 recipe_hooks["yaml"] = lambda do |recipe|
   expected = "-L" + File.join(recipe.path, "lib")
-  !$LDFLAGS.split.include?(expected) or raise "assertion failed on setup"
-
-  conf = pkg_config(File.join(recipe.path, "lib", "pkgconfig", "yaml-0.1.pc"))
-  puts "pkg_config: #{conf.inspect}"
-
   $LDFLAGS.split.include?(expected) or raise(<<~MSG)
     assertion failed: LDFLAGS not updated correctly:
     #{$LDFLAGS}
@@ -173,6 +168,7 @@ namespace :ports do
     recipes.each do |recipe|
       puts "Artifacts of '#{recipe.name}' in '#{recipe.path}'"
     end
+    puts "LIBRARY_PATH: #{ENV['LIBRARY_PATH'].inspect}"
     puts "LDFLAGS: #{ENV['LDFLAGS'].inspect}, #{$LDFLAGS.inspect}"
   end
 end

lib/mini_portile2/mini_portile.rb

@@ -32,7 +32,7 @@ class MiniPortile
 
   attr_reader :name, :version, :original_host
   attr_writer :configure_options
-  attr_accessor :host, :files, :patch_files, :target, :logger, :source_directory
+  attr_accessor :host, :files, :patch_files, :target, :logger, :source_directory, :set_ldflags
 
   def self.windows?
     target_os =~ /mswin|mingw/
@@ -85,6 +85,7 @@ def initialize(name, version, **kwargs)
     @log_files = {}
     @logger = STDOUT
     @source_directory = nil
+    @set_ldflags = true
 
     @original_host = @host = detect_host
 
@@ -238,14 +239,26 @@ def activate
       end
     end
 
-    # rely on LDFLAGS when cross-compiling
-    if File.exist?(lib_path) && (@host != @original_host)
-      full_path = File.expand_path(lib_path)
+    if set_ldflags && File.exist?(lib_path)
+      full_lib_path = File.expand_path(lib_path)
+      flag = "-L#{full_lib_path}"
 
-      old_value = ENV.fetch("LDFLAGS", "")
+      # rely on LDFLAGS when cross-compiling
+      if (@host != @original_host)
+        old_value = ENV.fetch("LDFLAGS", "")
 
-      unless old_value.include?(full_path)
-        ENV["LDFLAGS"] = "-L#{full_path} #{old_value}".strip
+        unless old_value.include?(full_lib_path)
+          ENV["LDFLAGS"] = "#{flag} #{old_value}".strip
+        end
+      end
+
+      # if we're in an extconf (mkmf.rb sets $LDFLAGS), append the library path. this works around
+      # an issue with fedora's pkgconf as detailed in:
+      #
+      #   https://github.com/flavorjones/mini_portile/issues/118
+      #
+      if $LDFLAGS && !$LDFLAGS.split.include?(flag)
+        $LDFLAGS << " #{flag}"
       end
     end
   end

test/test_activate.rb

@@ -9,6 +9,7 @@ def setup
     @save_env = %w[PATH CPATH LIBRARY_PATH].inject({}) do |env, var|
       env.update(var => ENV[var])
     end
+    $LDFLAGS = nil
 
     FileUtils.rm_rf(["tmp", "ports"]) # remove any previous test files
 
@@ -20,6 +21,7 @@ def setup
   def teardown
     FileUtils.rm_rf(["tmp", "ports"]) # remove any previous test files
 
+    $LDFLAGS = nil
     @save_env.each do |var, val|
       ENV[var] = val
     end
@@ -103,6 +105,34 @@ def test_LDFLAGS_env_var_when_cross_compiling
     assert(flag_elements('LDFLAGS').include?("-L#{lib_path}"))
   end
 
+  def test_LDFLAGS_global_when_not_set
+    $LDFLAGS = nil
+    FileUtils.mkdir_p(lib_path)
+
+    recipe.activate
+
+    assert_nil($LDFLAGS)
+  end
+
+  def test_LDFLAGS_global_when_set
+    $LDFLAGS = "-lm"
+    FileUtils.mkdir_p(lib_path)
+
+    recipe.activate
+
+    assert($LDFLAGS.split.include?("-L#{lib_path}"))
+  end
+
+  def test_LDFLAGS_global_when_set_but_option_is_turned_off
+    $LDFLAGS = "-lm"
+    FileUtils.mkdir_p(lib_path)
+
+    recipe.set_ldflags = false
+    recipe.activate
+
+    refute($LDFLAGS.split.include?("-L#{lib_path}"))
+  end
+
   private
 
   def path_elements(varname)