Add lconv declaration and localeconv(3)

lconv is taken from ndk/sources/android/support/include/locale.h and
matches
bsd/glibc upstream.
Keep old declaration for 32-bits for compatibility.
localeconv.c and deps are taken from openbsd upstream.
Changed strtod.c accordingly.

Change-Id: I9fcc4d15f5674d192950d80edf26f36006cd31b4
Signed-off-by: Pavel Chupin <pavel.v.chupin@intel.com>
diff --git a/libc/arch-mips64/mips64.mk b/libc/arch-mips64/mips64.mk
index 28806e1..9b29f0d 100644
--- a/libc/arch-mips64/mips64.mk
+++ b/libc/arch-mips64/mips64.mk
@@ -16,6 +16,11 @@
     upstream-freebsd/lib/libc/string/wcslen.c \
     upstream-freebsd/lib/libc/string/wcsrchr.c \
     upstream-freebsd/lib/libc/string/wmemcmp.c \
+    upstream-openbsd/lib/libc/locale/_def_numeric.c \
+    upstream-openbsd/lib/libc/locale/_def_messages.c \
+    upstream-openbsd/lib/libc/locale/_def_monetary.c \
+    upstream-openbsd/lib/libc/locale/_def_time.c \
+    upstream-openbsd/lib/libc/locale/localeconv.c \
     upstream-openbsd/lib/libc/string/bcopy.c \
     upstream-openbsd/lib/libc/string/strcat.c \
     upstream-openbsd/lib/libc/string/strcmp.c \