These improvements enable build systems to use GNUInstallDirs to define
custom directory variables.
- The set_dir() macro was renamed to GNUInstallDirs_set_install_dir(),
in keeping with the module's established macro naming convention.
- Rather than detecting whether the prefix has changed, the new
GNUInstallDirs_set_install_dir() macro instead examines whether the
default for the variable in question has changed. This allows for
more flexibility, since build systems may decide to change the
defaults based on factors other than the prefix. It also enables the
macro to work properly outside of the module.
- The module now performs directory variable substitution within the
body of GNUInstallDirs_get_absolute_install_dir().
- The JAVADIR variable is no longer included in GNUInstallDirs. That
directory is not part of the GNU spec, and it turns out that various
operating systems use different conventions for the location of Java
classes. Instead, the variable is now implemented in our build
system as a demonstration of the aforementioned GNUInstallDirs
enhancements.
- GNUInstallDirs: any directory variable can now reference any other
directory variable by including its name in angle brackets (<>).
- Changed the documentation of the directory variables in BUILDING.md
accordingly. This commit also includes some formatting tweaks to
that section (using boldface for directory names, as is our
convention.)
- Changed the package scripts such that they use
CMAKE_INSTALL_DATAROOTDIR rather than CMAKE_INSTALL_DATADIR.
- We no longer override the install dir. defaults on Windows unless
performing an official build. It may be useful, for instance, to
use the GNU defaults when installing into an MSYS environment.
This builds upon the existing GNUInstallDirs module in CMake but adds
the following features to that module:
- The ability to override the defaults for each install directory
through a new set of variables (`CMAKE_INSTALL_DEFAULT_*DIR`).
Before operating system vendors began shipping libjpeg-turbo, it was
meant to be a run-time drop-in replacement for the system's
distribution of libjpeg, so it has traditionally installed itself
under /opt/libjpeg-turbo on Un*x systems by default. On Windows, it
has traditionally installed itself under %SystemDrive%\libjpeg-turbo*,
which is not uncommon behavior for open source libraries (open source
SDKs tend to install outside of the Program Files directory so as to
avoid spaces in the directory name.) At least in the case of Un*x,
the install directory behavior is based somewhat on the Solaris
standard, which requires all non-O/S packages to install their files
under /opt/{package_name}. I adopted that standard for VirtualGL and
TurboVNC while working at Sun, because it allowed those packages to be
located under the same directory on all platforms. I adopted it for
libjpeg-turbo because it ensured that our files would never conflict
with the system's version of libjpeg. Even though many Un*x
distributions ship libjpeg-turbo these days, not all of them ship the
TurboJPEG API library or the Java classes or even the latest version
of the libjpeg API library, so there are still many cases in which it
is desirable to install a separate version of libjpeg-turbo than the
one installed by the system. Furthermore, installing the files under
/opt mimics the directory structure of our official binary packages,
and it makes it very easy to uninstall libjpeg-turbo.
For these reasons, our build system needs to be able to use
non-GNU-compliant defaults for each install directory if
`CMAKE_INSTALL_PREFIX` is set to the default value.
- For each directory variable, the module now detects changes to
`CMAKE_INSTALL_PREFIX` and changes the directory variable accordingly,
if the variable has not been changed by the user.
This makes it easy to switch between our "official" directory
structure and the GNU-compliant directory structure "on the fly"
simply by changing `CMAKE_INSTALL_PREFIX`. Also, this new mechanism
eliminated the need for the crufty mechanism that previously did the
same thing just for the library directory variable.
How it should work:
- If a dir variable is unset, then the module will set an internal
property indicating that the dir variable was initialized to its
default value.
- If the dir variable ever diverges from its default value, then the
internal property is cleared, and it cannot be set again without
unsetting the dir variable.
- If the install prefix changes, and if the internal property
indicates that the dir variable is still set to its default value,
and if the dir variable's value is not being manually changed at the
same time that the install prefix is being changed, then the dir
variable's value is automatically changed to the new default value
for that variable (as determined by the new install prefix.)
- The directory variables are now always cached, regardless of whether
they were set on the command line or not. This ensures that they can
easily be examined and modified after being set, regardless of how they
were set.
This was made possible by the introduction of the aforementioned
`CMAKE_INSTALL_DEFAULT_*DIR` variables.
- Improved directory variable documentation (based on descriptions at
https://www.gnu.org/prep/standards/html_node/Directory-Variables.html)
- The module now allows "<DATAROOTDIR>" to be used as a placeholder in
relative directory variables.
It is replaced "on the fly" with the actual path of
`CMAKE_INSTALL_DATAROOTDIR`.
This should more closely mimic the behavior of the old autotools build
system while retaining our customizations to it, and it should retain
the behavior of the old CMake build system.
Closes#124
- Replace CMAKE_SOURCE_DIR with CMAKE_CURRENT_SOURCE_DIR
- Replace CMAKE_BINARY_DIR with CMAKE_CURRENT_BINARY_DIR
- Don't use "libjpeg-turbo" in any of the package system filenames
(because CMAKE_PROJECT_NAME will not be the same if building LJT as
a submodule.)
Closes#122
Regression caused by f9134384b7
This commit also makes the "testclean" target clean up the 4:1:1 test
images. This was implemented in the autotools build system in
1f3635c496 but was left out of the CMake
build system due to an oversight.
When cross-compiling, CMakeLists.txt now generates the CTest script
using relative paths, so that CTest can more easily be executed on a
different machine from the build machine. Furthermore, Windows builds
are now tested using md5cmp, just like on Linux, rather than a CMake
script. This prevents issues with differing CMake locations between
the build and test machines.
This also removes some trailing spaces from the md5cmp code and improves
the readability of the test code in CMakeLists.txt.
