build: Fix various MacOS problems with GitHub and CMake

.github/workflows/ci.yml

@@ -520,34 +520,37 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - desc: MacOS-13-Intel llvm17
+          - desc: MacOS-13-Intel llvm17 oiio-release
             runner: macos-13
             nametag: macos13-p313
-            cc_compiler: /usr/local/opt/llvm/bin/clang
-            cxx_compiler: /usr/local/opt/llvm/bin/clang++
+            cc_compiler: clang
+            cxx_compiler: clang++
             cxx_std: 17
             python_ver: "3.13"
             aclang: 14
-            setenvs: export DO_BREW_UPDATE=0 CTEST_TEST_TIMEOUT=120
+            ctest_test_timeout: 120
+            setenvs: export HOMEBREW_PREFIX=/usr/local
                             EXTRA_BREW_PACKAGES="openimageio"
-          - desc: MacOS-14-ARM llvm17
+                            LLVMBREWVER="@17"
+          - desc: MacOS-14-ARM llvm19 oiio-release
             runner: macos-14
             nametag: macos14-arm-p313
             cc_compiler: clang
             cxx_compiler: clang++
             cxx_std: 17
             python_ver: "3.13"
             aclang: 15
-            setenvs: export DO_BREW_UPDATE=0
-                            EXTRA_BREW_PACKAGES="openimageio"
-          - desc: MacOS-15-ARM aclang16/C++17/py3.13
+            setenvs: export EXTRA_BREW_PACKAGES="openimageio"
+                            LLVMBREWVER="@19"
+          - desc: MacOS-15-ARM aclang16/C++17/py3.13 llvm19 oiio-main
             runner: macos-15
             nametag: macos15-arm-py313
             cc_compiler: clang
             cxx_compiler: clang++
             cxx_std: 17
             python_ver: "3.13"
             openimageio_ver: main
+            setenvs: export LLVMBREWVER="@19"
 
 
   windows:

src/build-scripts/install_homebrew_deps.bash

@@ -28,14 +28,18 @@ echo ""
 echo "Before my brew installs:"
 brew list --versions
 
-brew install --display-times -q gcc ccache cmake ninja || true
+if [[ "${BREW_UNLINK_PACKAGES}" != "" ]] ; then
+    brew unlink ${BREW_UNLINK_PACKAGES} || true
+fi
+
+
+if [[ "${DO_BREW_CMAKE_INSTALL:=1}" != "0" ]] ; then
+    brew install --display-times -q cmake || true
+fi
+brew install --display-times -q gcc ccache ninja || true
 brew link --overwrite gcc
 brew install --display-times -q python@${PYTHON_VERSION} || true
-# brew unlink python@3.8 || true
-# brew unlink python@3.9 || true
-brew unlink python@3.10 || true
 brew link --overwrite --force python@${PYTHON_VERSION} || true
-#brew upgrade --display-times -q cmake || true
 brew install --display-times -q imath openexr opencolorio || true
 #brew install --display-times -q freetype
 brew install --display-times -q partio pugixml || true

src/cmake/externalpackages.cmake

@@ -87,8 +87,9 @@ if (LLVM_VERSION VERSION_GREATER_EQUAL 16.0)
     if (CMAKE_COMPILER_IS_GNUCC AND (GCC_VERSION VERSION_LESS 7.0))
         message (WARNING "${ColorYellow}LLVM 16+ requires gcc 7.0 or higher.${ColorReset}\n")
     endif ()
-    if (CMAKE_COMPILER_IS_CLANG AND (CLANG_VERSION_STRING VERSION_LESS 5.0
-                                     OR APPLE_CLANG_VERSION_STRING VERSION_LESS 5.0))
+    if (CMAKE_COMPILER_IS_CLANG
+        AND NOT (CLANG_VERSION_STRING VERSION_GREATER_EQUAL 5.0
+                 OR APPLECLANG_VERSION_STRING VERSION_GREATER_EQUAL 5.0))
         message (WARNING "${ColorYellow}LLVM 16+ requires clang 5.0 or higher.${ColorReset}\n")
     endif ()
 endif ()

src/cmake/llvm_macros.cmake

@@ -60,7 +60,9 @@ function ( EMBED_LLVM_BITCODE_IN_CPP src_list suffix output_name list_to_append_
         endif ()
 
         if (APPLE)
-            list (APPEND LLVM_COMPILE_FLAGS -isysroot ${CMAKE_OSX_SYSROOT})
+            if (CMAKE_OSX_SYSROOT)
+                list (APPEND LLVM_COMPILE_FLAGS -isysroot ${CMAKE_OSX_SYSROOT})
+            endif ()
             if (CMAKE_OSX_DEPLOYMENT_TARGET)
                 list (APPEND LLVM_COMPILE_FLAGS -mmacosx-version-min=${CMAKE_OSX_DEPLOYMENT_TARGET})
             endif ()