Most software provides some means of setting build-time configuration options before compilation. Typically, setting these options is accomplished by running a configure script with some options, or by modifying a build configuration file.
A major part of build-time configuration is about checking for
build-time dependencies and possibly enabling optional
functionality as a result.
You need to specify any build-time dependencies for the
software you are building in your recipe's
DEPENDS
value, in terms of other recipes that satisfy those
dependencies.
You can often find build-time or runtime
dependencies described in the software's documentation.
The following list provides configuration items of note based on how your software is built:
Autotools:
If your source files have a
configure.ac
file, then your
software is built using Autotools.
If this is the case, you just need to worry about
modifying the configuration.
When using Autotools, your recipe needs to inherit
the
autotools
class and your recipe does not have to contain a
do_configure
task.
However, you might still want to make some adjustments.
For example, you can set
EXTRA_OECONF
to pass any needed configure options that are specific
to the recipe.
CMake:
If your source files have a
CMakeLists.txt
file, then your
software is built using CMake.
If this is the case, you just need to worry about
modifying the configuration.
When you use CMake, your recipe needs to inherit
the
cmake
class and your recipe does not have to contain a
do_configure
task.
You can make some adjustments by setting
EXTRA_OECMAKE
to pass any needed configure options that are specific
to the recipe.
Other:
If your source files do not have a
configure.ac
or
CMakeLists.txt
file, then your
software is built using some method other than Autotools
or CMake.
If this is the case, you normally need to provide a
do_configure
task in your recipe
unless, of course, there is nothing to configure.
Even if your software is not being built by Autotools or CMake, you still might not need to deal with any configuration issues. You need to determine if configuration is even a required step. You might need to modify a Makefile or some configuration file used for the build to specify necessary build options. Or, perhaps you might need to run a provided, custom configure script with the appropriate options.
For the case involving a custom configure
script, you would run
./configure ‐‐help
and look for
the options you need to set.
Once configuration succeeds, it is always good practice to
look at the log.do_configure
file to
ensure that the appropriate options have been enabled and no
additional build-time dependencies need to be added to
DEPENDS
.
For example, if the configure script reports that it found
something not mentioned in DEPENDS
, or
that it did not find something that it needed for some
desired optional functionality, then you would need to add
those to DEPENDS
.
Looking at the log might also reveal items being checked for,
enabled, or both that you do not want, or items not being found
that are in DEPENDS
, in which case
you would need to look at passing extra options to the
configure script as needed.
For reference information on configure options specific to the
software you are building, you can consult the output of the
./configure ‐‐help
command within
${S}
or consult the software's upstream
documentation.