* Add GNUInstallDirs for standard installation directories
Distributions are given standard variables for already existing hooks.
Multiarch libdirs is taken care of automagically.
Raises minimum cmake version by a little.
* Handle CMAKE_INSTALL_xxx being absolute paths for .pc file generation
In some cases the CMAKE_INSTAL_{BIN,MAN,DOC,LIB,INCLUDE}DIR variables
may turn out to be absolute paths in which case prepending ${prefix} in
the pkg-config .pc files will result in incorrect values.
For .pc file generation, figure out if these variables are absolute and
omit the prefix in the configured file when so.
See: ab25e4b7ed
Ancient versions of CMake required else(), endif(), and similar block termination commands to have arguments matching the command starting the block. This is no longer the preferred style.
Thanks to Hans Johnson
Ancient CMake versions required upper-case commands. Later command names became case-insensitive. Now the preferred style is lower-case.
This also changes all the key words to lower case. The primary reason for changing key words is that all documentation for CMakeLists.txt now shows the key words as lower case. Even the printed “Mastering CMake v5” uses lower case.
Thanks to Hans Johnson
Thomas Bracht Laumann Jespersen
Lemures Lemniscati
Mathieu Malaterre
Mickael Savinaud
Antonin Descampe
Ben Boeckel