fix(cmake): error wasn't triggering (#5676)

* fix(cmake): error wasn't triggering

Signed-off-by: Henry Schreiner <[email protected]>

* fix(cmake): wrong name of option

Signed-off-by: Henry Schreiner <[email protected]>

---------

Signed-off-by: Henry Schreiner <[email protected]>

Author: henryiii

CMakeLists.txt

@@ -65,10 +65,10 @@ if(CMAKE_SOURCE_DIR STREQUAL PROJECT_SOURCE_DIR)
 
   message(STATUS "CMake ${CMAKE_VERSION}")
 
-  if(DEFINED SKBUILD AND DEFINED $ENV{PYBIND11_GLOBAL_PREFIX})
+  if(DEFINED SKBUILD AND DEFINED ENV{PYBIND11_GLOBAL_SDIST})
     message(
       FATAL_ERROR
-        "PYBIND11_GLOBAL_PREFIX is not supported, use nox -s build_global or a pybind11-global SDist instead."
+        "PYBIND11_GLOBAL_SDIST is not supported, use nox -s build_global or a pybind11-global SDist instead."
     )
   endif()