midl /no_def_idir <other-options> filename
; search only the current directory
midl /no_def_idir filename.idl
; search only the specified directories
midl /no_def_idir /I c:\c700\include filename.idl
When directories are specified with the /I switch, the /no_def_idir switch instructs the MIDL compiler to search only the directories specified with the /I switch, ignoring the current directory and ignoring the directories specified by the INCLUDE environment variable.
When no directories are specified with the /I switch, the /no_def_idir switch instructs the MIDL compiler to search only the current directory.
General MIDL Command-line Syntax, /acf, /I