Fix more endian.h issues

__BIONIC__ is defined in sys/cdefs.h, __GLIBC__ is defined in
features.h (which is included from sys/cdefs.h).  If sys/cdefs.h
was not included before android-base/endian.h it was always falling
back to the Windows definitions.

mingw defines LITTLE_ENDIAN, BIG_ENDIAN and BYTE_ORDER in
sys/params.h, use those definitions to avoid conflicts.

glibc uses different names for letoh*, add compatibily #defines.

Test: m checkbuild
Change-Id: I0709a964cc8f20dd9fa4f03064cc67d97ae6c525