Restore support for anistropic filtering on macos

Author: Rye

indra/llrender/llgl.cpp

@@ -1254,7 +1254,7 @@ bool LLGLManager::initGL()
     // there's some implementation that reports a crazy value
     mMaxUniformBlockSize = llmin(mMaxUniformBlockSize, 65536);
 
-    if (mGLVersion >= 4.59f)
+    if (mHasAnisotropic)
     {
         glGetFloatv(GL_MAX_TEXTURE_MAX_ANISOTROPY, &mMaxAnisotropy);
     }
@@ -1421,6 +1421,11 @@ void LLGLManager::initExtensions()
     mHasCubeMapArray = mGLVersion >= 3.99f;
     mHasTransformFeedback = mGLVersion >= 3.99f;
     mHasDebugOutput = mGLVersion >= 4.29f;
+    mHasAnisotropic = mGLVersion >= 4.59f;
+    if(!mHasAnisotropic && gGLHExts.mSysExts)
+    {
+        mHasAnisotropic = ExtensionExists("GL_EXT_texture_filter_anisotropic", gGLHExts.mSysExts);
+    }
 
 #if LL_WINDOWS || LL_LINUX
     if( gGLHExts.mSysExts )

indra/llrender/llrender.cpp

@@ -517,7 +517,7 @@ void LLTexUnit::setTextureFilteringOption(LLTexUnit::eTextureFilterOptions optio
         }
     }
 
-    if (gGLManager.mGLVersion >= 4.59f)
+    if (gGLManager.mHasAnisotropic)
     {
         if (LLImageGL::sGlobalUseAnisotropic && option == TFO_ANISOTROPIC)
         {