Set system include, library paths and flags

--- build_config.rb.orig	Sun Feb  7 21:44:01 2021
+++ build_config.rb	Wed Mar 10 16:17:26 2021
@@ -57,7 +57,6 @@ build_type.new(build_name) do |conf|
   enable_debug
 
   conf.cc.defines = %w(MRUBY_NANOVG_GL2 MRB_ENABLE_DEBUG_HOOK)
-  conf.cc.flags << '-O3'
 
   #No default gems
   # Use standard print/puts/p
@@ -113,6 +112,8 @@ build_type.new(build_name) do |conf|
   end
 
   conf.cc do |cc|
+      cc.include_paths << "${LOCALBASE}/include"
+      cc.include_paths << "${X11BASE}/include"
       cc.include_paths << "#{`pwd`.strip}/../deps/nanovg/src"
       cc.include_paths << "#{`pwd`.strip}/../deps/pugl/"
       cc.include_paths << "#{`pwd`.strip}/../deps/libuv/include/" if !linux
@@ -131,6 +132,8 @@ build_type.new(build_name) do |conf|
   end
 
   conf.linker do |linker|
+      linker.library_paths  << "${LOCALBASE}/lib"
+      linker.library_paths  << "${X11BASE}/lib"
       linker.library_paths  << "#{`pwd`.strip}/../src/osc-bridge/"
       linker.libraries << 'osc-bridge'
       linker.flags_after_libraries  << "#{`pwd`.strip}/../deps/libnanovg.a"
@@ -142,7 +145,7 @@ build_type.new(build_name) do |conf|
         else
           linker.flags_after_libraries  << "#{`pwd`.strip}/../deps/libuv.a"
         end
-        linker.flags_after_libraries  << "-lpthread -ldl -lm"
+        linker.flags_after_libraries  << "-lpthread -lm"
       else
         linker.flags_after_libraries  << "#{`pwd`.strip}/../deps/libuv-win.a"
         linker.flags_after_libraries  << "-lws2_32 -lkernel32 -lpsapi -luserenv -liphlpapi"