set PERL5LIB=\perl\lib;\perl\site\lib

##</code><code>##

set PERL5LIB=foo;bar;%PERL5LIB%

##</code><code>##

......
  %ENV:
    PERL5LIB="foo;bar;\perl\lib;\perl\site\lib"
  @INC:
    foo
    bar
    \perl\lib
    \perl\site\lib
    .