Bump version to 2.4.0.pre1 for future development.
release process:
1. master will always be pre release version
2. branch will have official release such as 2.3.0, 2.3.1,2.4.0
3. after branch out release branch, minor version will be bumped.
Signed-off-by: XinfengZhang <carl.zhang@intel.com>
v2: remove gtest meson file
v3: install binaries
respect disabled libraries
apply cpp_args to all test files
add full version
v4: define HAVE_* macros
v5: Downgrade meson requirement to 0.42.0