Added ability to disable required OSX_SYSROOT cmake checks

.github/workflows/build.yaml

@@ -30,6 +30,7 @@ jobs:
       DEVELOPER_DIR: ${{ matrix.developer_dir }}
       LOGFAIL: debug # Show details when tests fail
       GIT_REF: ${{ github.head_ref || github.ref }}
+      LL_SKIP_REQUIRE_SYSROOT: 1
     steps:
       - name: Checkout code
         uses: actions/checkout@v3

indra/cmake/Variables.cmake

@@ -173,13 +173,17 @@ if (${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
   set(CMAKE_XCODE_ATTRIBUTE_GCC_OPTIMIZATION_LEVEL "${CMAKE_MATCH_1}")
   message(STATUS "CMAKE_XCODE_ATTRIBUTE_GCC_OPTIMIZATION_LEVEL = '${CMAKE_XCODE_ATTRIBUTE_GCC_OPTIMIZATION_LEVEL}'")
 
-  string(REGEX MATCHALL "[^ ]+" LL_BUILD_LIST "$ENV{LL_BUILD}")
-  list(FIND LL_BUILD_LIST "-iwithsysroot" sysroot_idx)
-  if ("${sysroot_idx}" LESS 0)
-    message(FATAL_ERROR "Environment variable LL_BUILD must contain '-iwithsysroot'")
-  endif ()
-  math(EXPR sysroot_idx "${sysroot_idx} + 1")
-  list(GET LL_BUILD_LIST "${sysroot_idx}" CMAKE_OSX_SYSROOT)
+  # allow disabling this check by setting LL_SKIP_REQUIRE_SYSROOT either ON as cmake cache var or non-empty as environment var
+  set(LL_SKIP_REQUIRE_SYSROOT OFF CACHE BOOL "Skip requirent to set toolchain sysroot ahead of time. Not skipped by default for consistency, but skipping can be useful for selecting alternative xcode versions side by side")
+  if("$ENV{LL_SKIP_REQUIRE_SYSROOT}" STREQUAL "" AND NOT ${LL_SKIP_REQUIRE_SYSROOT})
+    string(REGEX MATCHALL "[^ ]+" LL_BUILD_LIST "$ENV{LL_BUILD}")
+    list(FIND LL_BUILD_LIST "-iwithsysroot" sysroot_idx)
+    if ("${sysroot_idx}" LESS 0)
+      message(FATAL_ERROR "Environment variable LL_BUILD must contain '-iwithsysroot'")
+    endif ()
+    math(EXPR sysroot_idx "${sysroot_idx} + 1")
+    list(GET LL_BUILD_LIST "${sysroot_idx}" CMAKE_OSX_SYSROOT)
+  endif()
   message(STATUS "CMAKE_OSX_SYSROOT = '${CMAKE_OSX_SYSROOT}'")
 
   set(CMAKE_XCODE_ATTRIBUTE_GCC_VERSION "com.apple.compilers.llvm.clang.1_0")