5.2.2 #IFNDEF

Syntax:

#IFNDEF name

Lines following #IFNDEF are skipped read if the keyword name following it is dened.

They are read until the keywords #ELSE or #ENDIF are encountered, after which normal processing is resumed.

Example :

#IFNDEF VER0_99_5  
-Fu/usr/lib/fpc/0.99.6/linuxunits  
#ENDIF

In the above example, /usr/lib/fpc/0.99.6/linuxunits will be added to the path if you're NOT compiling with version 0.99.5 of the compiler.