/PLUS_LIST_OPTIMIZE

    /PLUS_LIST_OPTIMIZE
    /NOPLUS_LIST_OPTIMIZE (D)

 Provides improved optimization and code generation across file
 boundaries that would not be available if the files were compiled
 seperately.

 When you specify /PLUS_LIST_OPTIMIZE on the command line in
 conjunction with a series of file specifications separated by plus
 signs, the compiler does not concatenate each of the specified
 source files together.  Instead, each file is treated separately
 for purposes of parsing, except that the compiler will issue
 diagnostics about conflicting external declarations and function
 definitions that occur in different files.  For purposes of code
 generation, the compiler treats the files as one application.

 The default is /NOPLUS_LIST_OPTIMIZE.