strptime: make flb_strptime.c actually usable
strptime: make flb_strptime.c actually usable

This patch adds many missing bits in order to make flb_strptime.c
compilable and linkable. The changeset includes:

 - Rename the function to flb_strptime to avoid conflicts with the
   existing definition.
 - Use nl_langinfo() instead of _ctloc() for portability.
 - Use FLB_HAVE_* macros for ifdef blocks.

Signed-off-by: Fujimoto Seiji <ef879192bb1e41d519c82cf76440dc8e9a530806@clear-code.com>

fluent/fluent-bit,nokute78/fluent-bit,fluent/fluent-bit,nokute78/fluent-bit,fluent/fluent-bit,nokute78/fluent-bit,fluent/fluent-bit,nokute78/fluent-bit,fluent/fluent-bit,fluent/fluent-bit,nokute78/fluent-bit,fluent/fluent-bit,fluent/fluent-bit,nokute78/fluent-bit,nokute78/fluent-bit,fluent/fluent-bit,nokute78/fluent-bit,nokute78/fluent-bit,nokute78/fluent-bit,nokute78/fluent-bit,fluent/fluent-bit,nokute78/fluent-bit,fluent/fluent-bit,fluent/fluent-bit