+ # Guess yes on glibc systems.
+ *-gnu*) gl_cv_func_printf_directive_f="guessing yes";;
+ # Guess yes on FreeBSD >= 6.
+ freebsd[1-5]*) gl_cv_func_printf_directive_f="guessing no";;
+ freebsd* | kfreebsd*) gl_cv_func_printf_directive_f="guessing yes";;
+ # Guess yes on MacOS X >= 10.3.
+ darwin[1-6].*) gl_cv_func_printf_directive_f="guessing no";;
+ darwin*) gl_cv_func_printf_directive_f="guessing yes";;
+ # Guess yes on Solaris >= 2.10.
+ solaris2.[0-9]*) gl_cv_func_printf_directive_f="guessing no";;
+ solaris*) gl_cv_func_printf_directive_f="guessing yes";;