sizeof(time_t) was previously switched from 4 to 8, ROM functions that use
time_t or dependent types (such as "struct stat") are no longer called due as
they still treat sizeof(time_t) as 4 (see commit
24c20d188e).
However, there is a ROM callpath that was left out. If putchar is the first
stdio print related call, the call path will result in cantwrite() ->
__swsetup_r() -> __smakebuf_r() -> __swhatbuf_r() using the ROM "struct stat"
(where sizeof(time_t)==4).
Instead of removing all printf related ROM newlib functions (which will result
in increased binary size), this commit adds a workaround to setup the stdio
files before any print related calls occur.
This results in cantwrite() always returning false, thus the callpath described
above never being reached.
Closes https://github.com/espressif/esp-idf/issues/9269
jiangguangming