Update OCIO to 2.4.2 on MacOS

   This is to avoid build issues resulting from Xcode 26.

(Internal change: 2406844)

Author: tallytalwar

CHANGELOG.md

@@ -10,6 +10,8 @@
     (PR: [#3707](https://github.com/PixarAnimationStudios/OpenUSD/pull/3707))
   - Fixed a bug where OpenImageIO would not use the OpenColorIO library built by
     build_usd.py if both were enabled.
+  - Updated OCIO version to 2.4.2 for macOS builds, to avoid build issues with 
+    latest versions of Xcode (26).
 
 - Removed support for Python 3.8 and added support for Python 3.14 for the 
   usd-core PyPI package.

VERSIONS.md

@@ -21,7 +21,7 @@ Our test machines have the following software versions installed.
 | OneTBB        | 2021.9               | 2021.9                       | 2021.9                         |
 | OpenSubdiv    | 3.6.1                | 3.6.1                        | 3.6.1                          |
 | OpenImageIO   | 2.5.16.0             | 2.5.16.0                     | 2.5.16.0                       |
-| OpenColorIO   | 2.2.1                | 2.2.1                        | 2.2.1                          |
+| OpenColorIO   | 2.2.1                | 2.4.2                        | 2.2.1                          |
 | OSL           | 1.13.11              |                              |                                |
 | Ptex          | 2.4.2                | 2.4.2                        | 2.4.2                          |
 | Qt for Python | PySide2 5.15.2.1     | PySide6 6.3.1                | PySide2 5.15.2.1               |

build_scripts/build_usd.py

@@ -1470,10 +1470,16 @@ def InstallOpenImageIO(context, force, buildArgs):
 ############################################################
 # OpenColorIO
 
-OCIO_URL = "https://github.com/AcademySoftwareFoundation/OpenColorIO/archive/refs/tags/v2.2.1.zip"
+if MacOS():
+    OCIO_URL = "https://github.com/AcademySoftwareFoundation/OpenColorIO/archive/refs/tags/v2.4.2.zip"
+else:
+    OCIO_URL = "https://github.com/AcademySoftwareFoundation/OpenColorIO/archive/refs/tags/v2.2.1.zip"
 
 def InstallOpenColorIO(context, force, buildArgs):
-    with CurrentWorkingDirectory(DownloadURL(OCIO_URL, context, force)):
+    # build ocio dest file name based on the OCIO_URL version
+    ocioDestFileName = os.path.splitext(os.path.basename(OCIO_URL))[0]
+    with CurrentWorkingDirectory(DownloadURL(OCIO_URL, context, force,
+                                             destFileName=ocioDestFileName)):
         extraArgs = ['-DOCIO_BUILD_APPS=OFF',
                      '-DOCIO_BUILD_DOCS=OFF',
                      '-DOCIO_BUILD_TESTS=OFF',