--- SConstruct.orig	2024-02-02 13:19:31 UTC
+++ SConstruct
@@ -66,7 +66,7 @@ if env['werror']:
     env.Append(CCFLAGS='-Werror')
 
 if env['mode'] not in ['debug', 'analyze']:
-    env.Append(CPPDEFINES='NDEBUG', CCFLAGS='-Ofast')
+    env.Append(CPPDEFINES='NDEBUG')
 
 if env['mode'] == 'debug':
     env.Append(CCFLAGS=['-O0'])
@@ -84,15 +84,13 @@ for root, dirnames, filenames in os.walk('src'):
         if filename.endswith('.c') or filename.endswith('.cpp'):
             sources.append(os.path.join(root, filename))
 
-# Check for libpng.
-if conf.CheckLibWithHeader('libpng', 'png.h', 'c'):
-    env.Append(CPPDEFINES='HAVE_LIBPNG=1')
-
 # Linux compilation support.
 if target_os == 'posix':
+    env.Append(CPPDEFINES='HAVE_LIBPNG=1')
     env.Append(LIBS=['GL', 'm', 'dl', 'pthread'])
     # Note: add '--static' to link with all the libs needed by glfw3.
-    env.ParseConfig('pkg-config --libs glfw3')
+    env.ParseConfig('pkg-config --cflags --libs glfw3')
+    env.ParseConfig('pkg-config --libs libpng')
 
 # Windows compilation support.
 if target_os == 'msys':