Fixup: define variables needed in the enable_languages macro with the correct scope

Author: ptheywood

cmake/enable_languages.cmake

@@ -15,16 +15,9 @@ include_guard(GLOBAL)
 include(CheckLanguage)
 include(CheckSourceCompiles)
 
-# Define the minimum supported CUDA and HIP versions
-set(MINIMUM_SUPPORTED_CUDA_VERSION 12.4)
-set(MINIMUM_SUPPORTED_HIP_VERSION 7.0)  # patch version differs from the rocm package 
-
-# Set the std which is used in compilation testing examples
-set(_flamegpu_cxx_std 20)
-
 # Define a cache variable FLAMEGPU_GPU controlling the GPU API to use, defaulting to CUDA in the GUI.
 set(_FLAMEGPU_GPU_OPTIONS "CUDA;HIP;OFF")
-set(FLAMEGPU_GPU "CUDA" CACHE STRING "The GPU API to use. Choose from ${_FLAMEGPU_GPU_OPTIONS}. Use OFF for a documentation-only build." )
+set(FLAMEGPU_GPU "CUDA" CACHE STRING "The GPU API to use. Choose from ${_FLAMEGPU_GPU_OPTIONS}. Use OFF for a documentation-only build.")
 set_property(CACHE FLAMEGPU_GPU PROPERTY STRINGS ${_FLAMEGPU_GPU_OPTIONS})
 # Validate that FLAMEGPU_GPU is set to an allowed value
 if(NOT "${FLAMEGPU_GPU}" IN_LIST _FLAMEGPU_GPU_OPTIONS)
@@ -39,6 +32,13 @@ macro(flamegpu_enable_languages)
         message(FATAL_ERROR "flamegpu_enable_languages must be called after a call to 'project()'")
     endif()
 
+    # Define some local variables in macro-scope so they are available when required (when included by other projects, i.e. templates)
+    # Define the minimum supported CUDA and HIP versions
+    set(MINIMUM_SUPPORTED_CUDA_VERSION 12.4)
+    set(MINIMUM_SUPPORTED_HIP_VERSION 7.0)  # patch version differs from the rocm package
+    # Set the std which is used in compilation testing examples
+    set(_flamegpu_cxx_std 20)
+
     # Check for Host and Device compiler support if not in an intentional documentation-only build
     if (NOT ${FLAMEGPU_GPU} STREQUAL "OFF")
         # Get the currently enabled languages, so that if a parent project has HIP enabled but FLAMEGPU is configured for CUDA we can raise an appropriate warning/error