Defining macros
---------------
The general syntax for defining a macro in a makefile is:

        MacroName = expansion_text

  o  "MacroName" is case-sensitive and is limited to 512 characters.

  o  "expansion_text" is limited to 4096 characters consisting of
     alpha-numeric characters, punc-tuation, and white space.

Each macro must be on a separate line in a makefile. Macros are
usually put at the top of the makefile. If MAKE finds more than one
definition for a "macroName", the new definition replaces the old one.

Macros can also be defined using the command-line option -D. More than
one macro can be defined by separating them with spaces. The following
examples show macros defined at the command line:

  make -Dsourcedir=c:\projecta
  make command="bcc -c"
  make command=bcc option=-c

The following differences in syntax exist between macros entered on
the command line and macros written in a makefile.

                        Makefile        Command line
                        --------        ------------
Spaces allowed before
and after =             Yes             No

Space allowed before
macroName               No              Yes