Use lower case style for commands
Where possible this syncs the CS for command names:
- check_c_source_compiles()
- check_cxx_compiler_flag()
- check_cxx_source_compiles()
- check_cxx_symbol_exists()
- check_include_file_cxx()
- check_include_file()
- check_include_files()
- check_library_exists()
- check_source_compiles()
- check_struct_has_member()
- check_symbol_exists()
- check_type_size()
- cmake_dependent_option()
- cmake_parse_arguments()
- feature_summary()
- file()
- find_package_handle_standard_args()
- if(), endif...
- install(FILES)
- list()
- message()
- pkg_check_modules()
- select_library_configurations()
- set_package_info()
- test_big_endian()
115 files changed
