Build dynamic library with a Linux-qualified name(s)

[dvrogozh]

By convention on Linux if library is going to be linked against it should have:

• real name, which is usually libigdgmm.so.x.y.z, x.y.z is a library version
• soname which is libigdgmm.so.x, usually that's a symbolic link to real name
• linker name which is libigdgmm.so, usually that's a symbolic link to soname
  Building library without the above convention is applicable only if library is supposed to be dlopen(), i.e. for drivers and similar things.

Since gmmlib will be linked against rahter than dlopen-ed it should qualify to the above Linux convention. This fix makes exactly that. CMake will automatically create required symbolc links (soname and linker name).

Mind also that it is typical to break these target in the following way for the packages:

• real name and soname goes to runtime package (the one without *.h and *.pc files)
• linker name goes to devel package (the one with *.h and *.pc files)

This can be achieved setting the following targets over the cmake target:

set_target_properties(${GMM_LIB_DLL_NAME} PROPERTIES VERSION ${MAJOR_VERSION}.${MINOR_VERSION}.${PATCH_VERSION})
set_target_properties(${GMM_LIB_DLL_NAME} PROPERTIES SOVERSION ${MAJOR_VERSION})

Could you, please, make such a change?