Convert to boolean in C code

casecmp?(str) is 1.5x faster than casecmp(str).zero?
It's 1 less method call in Ruby, and the C code can convert
to boolean, rather than returning a number and determining
if it's zero.

app/helpers/jsonld_helper.rb

@@ -53,7 +53,7 @@ module JsonLdHelper
     needle   = Addressable::URI.parse(url).host
     haystack = Addressable::URI.parse(@account.uri).host
 
-    !haystack.casecmp(needle).zero?
+    !haystack.casecmp?(needle)
   end
 
   def canonicalize(json)

app/lib/tag_manager.rb

@@ -7,11 +7,11 @@ class TagManager
   include RoutingHelper
 
   def web_domain?(domain)
-    domain.nil? || domain.gsub(/[\/]/, '').casecmp(Rails.configuration.x.web_domain).zero?
+    domain.nil? || domain.gsub(/[\/]/, '').casecmp?(Rails.configuration.x.web_domain)
   end
 
   def local_domain?(domain)
-    domain.nil? || domain.gsub(/[\/]/, '').casecmp(Rails.configuration.x.local_domain).zero?
+    domain.nil? || domain.gsub(/[\/]/, '').casecmp?(Rails.configuration.x.local_domain)
   end
 
   def normalize_domain(domain)
@@ -35,9 +35,9 @@ class TagManager
   end
 
   def same_acct?(canonical, needle)
-    return true if canonical.casecmp(needle).zero?
+    return true if canonical.casecmp?(needle)
     username, domain = needle.split('@')
-    local_domain?(domain) && canonical.casecmp(username).zero?
+    local_domain?(domain) && canonical.casecmp?(username)
   end
 
   def local_url?(url)

config/initializers/open_uri_redirection.rb

@@ -2,7 +2,7 @@ require 'open-uri'
 
 module OpenURI
   def self.redirectable?(uri1, uri2) # :nodoc:
-    uri1.scheme.casecmp(uri2.scheme).zero? ||
+    uri1.scheme.casecmp?(uri2.scheme) ||
       (/\A(?:http|https|ftp)\z/i =~ uri1.scheme && /\A(?:http|https|ftp)\z/i =~ uri2.scheme)
   end
 end

lib/gabsocial/migration_helpers.rb

@@ -44,13 +44,13 @@ module GabSocial
     # Stub for Database.postgresql? from GitLab
     def self.postgresql?
       %w[postgresql postgresql_makara].any? do |adapter|
-        ActiveRecord::Base.configurations[Rails.env]['adapter'].casecmp(adapter).zero?
+        ActiveRecord::Base.configurations[Rails.env]['adapter'].casecmp?(adapter)
       end
     end
 
     # Stub for Database.mysql? from GitLab
     def self.mysql?
-      ActiveRecord::Base.configurations[Rails.env]['adapter'].casecmp('mysql2').zero?
+      ActiveRecord::Base.configurations[Rails.env]['adapter'].casecmp?('mysql2')
     end
 
     # Model that can be used for querying permissions of a SQL user.