src/cmake/DawnSetIfNotDefined.cmake

# Copyright 2024 The Dawn & Tint Authors
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# set_if_not_defined(name value description)
# Behaves like:
#   set(${name} ${value} CACHE STRING ${description})
# If a variable is not already defined with the given name, otherwise the
# function does nothing.
# Simplifies customization by projects that use Dawn as a dependency.
# Usages of set_if_not_defined can be safely replaced with `set` after
# the minimum cmake version is bumped to >= 3.20
function(set_if_not_defined name value description)
  if(NOT DEFINED ${name})
    set(${name} ${value} CACHE STRING ${description})
  endif()
endfunction()