/EXTERN_MODEL

    /EXTERN_MODEL=option
    /EXTERN_MODEL=RELAXED_REFDEF (D)

 In conjunction with the /SHARE_GLOBALS qualifier, controls the
 initial extern model of the compiler.  Conceptually, the compiler
 behaves as if the first line of the program being compiled was a
 #pragma extern_model directive with the model and psect name, if
 any, specified by the /EXTERN_MODEL qualifier and with the shr or
 noshr keyword specified by the /SHARE_GLOBALS qualifier.

 For example, assume the command line contains the following
 qualifier:

      /EXTERN_MODEL=STRICT_REFDEF="MYDATA"/NOSHARE

 The compiler will act as if the program began with the following
 line:

      #pragma extern_model strict_refdef "MYDATA" noshr

 See also #pragma extern_model.

 The /EXTERN_MODEL qualifier takes the following options, which have
 the same meaning as for the #pragma extern_model directive:

 COMMON_BLOCK

 RELAXED_REFDEF

 STRICT_REFDEF

 STRICT_REFDEF="NAME"

 GLOBALVALUE

 The default model on VSI C is relaxed/refdef with the noshare
 attribute.  This is different from the model used by VAX C, which
 is common block, share.