Each package can be customized to your liking. Because GNU packages follow a standardized build process, customizing the GSRC build for one is straightforward.
GNU packages take most of their configuration in the form of options
passed to the configure script. One may easily customize these
options in a GSRC Makefile by setting the
variable. Any options added to this variable will be appended to the
options set by default by GSRC.
CONFIGURE_OPTS = --disable-gtk --without-png
For convenience, every package has a file called config.mk in
its directory which is imported by its build script. Typically, all
user configuration may be done here. By default, it contains the
BUILD_OPTS variables. In some special
cases, package-specific, user-customize-able variables are also
defined in this file.
Generally speaking, user configuration is done exclusively in config.mk while Makefile contains the information and recipe necessary for the package to build correctly. Thus, you should not need to modify the Makefile unless you have special requirements. Note that most configuration options relating to directory locations (such as where to install, where to search for libraries, etc.) are set in the Makefile, because they are necessary for proper building and installation in GSRC. Therefore, you do not need to worry about setting them correctly in config.mk.