$ ./configure --enable-developer -n Compiling ccan/tools/configurator/configurator... done -n checking for python3-mako... found Making autoconf users comfortable... yes checking for off_t is 32 bits... no checking for __alignof__ support... yes checking for asprintf() declaration... yes checking for __attribute__((cold)) support... yes checking for __attribute__((const)) support... yes checking for __attribute__((deprecated)) support... no checking for __attribute__((nonnull)) support... yes checking for __attribute__((sentinel)) support... yes checking for __attribute__((pure)) support... yes checking for __attribute__((may_alias)) support... yes checking for __attribute__((noreturn)) support... yes checking for __attribute__ format printf support... yes checking for __attribute__((unused)) support... yes checking for __attribute__((used)) support... yes checking for backtrace() in ... yes checking for big endian... no checking for ... no checking for __builtin_choose_expr support... yes checking for __builtin_clz support... yes checking for __builtin_clzl support... yes checking for __builtin_clzll support... yes checking for __builtin_ctz support... yes checking for __builtin_ctzl support... yes checking for __builtin_ctzll support... yes checking for __builtin_constant_p support... yes checking for __builtin_expect support... yes checking for __builtin_ffs support... yes checking for __builtin_ffsl support... yes checking for __builtin_ffsll support... yes checking for __builtin_popcount support... yes checking for __builtin_popcountl support... yes checking for __builtin_popcountll support... yes checking for __builtin_types_compatible_p support... yes checking for ... no checking for struct timespec declaration... yes checking for clock_gettime() declaration... yes checking for compound literal support... yes checking for fchdir support... yes checking for ... yes checking for for loop declaration support... yes checking for flexible array member support... yes checking for getpagesize() in ... yes checking for isblank() in ... yes checking for little endian... yes checking for memmem in ... yes checking for memrchr in ... no checking for mmap() declaration... yes checking for /proc/self/maps exists... no checking for qsort_r cmp takes trailing arg... no checking for __attribute__((section)) and __start/__stop... no checking for stack grows upwards... no checking for statement expression support... yes checking for ... yes checking for ... yes checking for ... yes checking for __typeof__ support... yes checking for unaligned access to int... yes checking for utime() declaration... yes checking for __attribute__((warn_unused_result))... yes checking for #pragma omp and -fopenmp support... no checking for ... no checking for working