test/Modules/Inputs/System/usr/include/module.map

module cstd [system] {
  // Only in compiler support directory
  module float_constants {
    header "float.h"
  }

  // Only in system headers directory
  module stdio {
    header "stdio.h"
  }

  // In both directories (compiler support version wins, does not forward)
  module stdbool {
    header "stdbool.h"
  }

  // In both directories (compiler support version wins, forwards)
  module stdint {
    header "stdint.h"
  }
}