This fixes the dependency checks inside of setup.py since things like
'import numpy' won't work with bitbake.

diff --git a/setup.py b/setup.py
index 2f13821..e6d6ed0 100644
--- a/setup.py
+++ b/setup.py
@@ -113,12 +113,6 @@ if 1:
     baseline_images = [chop_package(f) for f in baseline_images]
     package_data['matplotlib'].extend(baseline_images)
 
-if not check_for_numpy():
-    sys.exit(1)
-
-if not check_for_freetype():
-    sys.exit(1)
-
 build_ft2font(ext_modules, packages)
 build_ttconv(ext_modules, packages)
 build_contour(ext_modules, packages)
@@ -129,7 +123,7 @@ build_tri(ext_modules, packages)
 
 print_raw("")
 print_raw("OPTIONAL BACKEND DEPENDENCIES")
-has_libpng = check_for_libpng()
+has_libpng = True
 
 if has_libpng and options['build_agg']:
     build_agg(ext_modules, packages)