tzselect: workaround bug in busybox awk

busybox's version of awk in version 1.20.2 and lower doesn't support
escape sequences in conjunction with the -F option. Use -v FS= instead
as a workaround until the bug is fixed.

Reference:
https://bugs.busybox.net/show_bug.cgi?id=5126

Upstream-Status: Inappropriate [other]

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>

--- libc/timezone/tzselect.ksh
+++ libc/timezone/tzselect.ksh
@@ -208,7 +208,7 @@ while
 		TZ_for_date=$TZ;;
 	*)
 		# Get list of names of countries in the continent or ocean.
-		countries=$($AWK -F'\t' \
+		countries=$($AWK -v FS="\t" \
 			-v continent="$continent" \
 			-v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 		'
@@ -252,7 +252,7 @@ while
 
 
 		# Get list of names of time zone rule regions in the country.
-		regions=$($AWK -F'\t' \
+		regions=$($AWK -v FS="\t" \
 			-v country="$country" \
 			-v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 		'
@@ -289,7 +289,7 @@ while
 		esac
 
 		# Determine TZ from country and region.
-		TZ=$($AWK -F'\t' \
+		TZ=$($AWK -v FS="\t" \
 			-v country="$country" \
 			-v region="$region" \
 			-v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \