Macro Definitions

A macro definition is an identifier followed by the symbol =. The identifier must not be preceded by a colon (:) or a tab. The name (string of letters and digits) to the left of the = (trailing blanks and tabs are stripped) is assigned the string of characters following the =+ (leading blanks and tabs are stripped). The following are valid macro definitions:

2 = xyz 
abc = -ll -ly -lm 
LIBES =

The last definition assigns LIBES the null string. A macro that is never explicitly defined has the null string as its value. Remember, however, that some macros are explicitly defined in make's own rules. (See "Internal Rules ".)