I encountered the following error when trying to compile the library (latest on master, 032c838) on Ubuntu 16.04.3 LTS (gcc 5.4.0):
In file included from /home/f/Documents/repos/fmt/fmt/format.cc:28:0:
/home/f/Documents/repos/fmt/fmt/format.h:146:23: error: expected unqualified-id before ‘[’ token
# define FMT_NORETURN [[noreturn]]
^
/home/f/Documents/repos/fmt/fmt/format.h:935:9: note: in expansion of macro ‘FMT_NORETURN’
FMT_API FMT_NORETURN void report_unknown_type(char code, const char *type);