Added recipe for libpng.

recipes/libpng/recipe.py

@@ -0,0 +1,12 @@
+
+from SCons.Script import *
+
+def cook(env: Environment, git_ref = 'master') -> dict:
+    repo = env.Cook('GitBranch', repo_name = 'libpng', remote_url = 'https://git.code.sf.net/p/libpng/code.git', git_ref = git_ref)
+    checkout_root = repo['checkout_root']
+    build_result = env.Cook('AutotoolsProject', checkout_root)
+    return {
+        'LIBPATH': build_result['LIBPATH'],
+        'CPPPATH': build_result['CPPPATH'],
+        'LIBS': ['png']
+    }