merge_config.sh: Use the first file as the initial config

Take the first config fragment and use it verbatim as the initial config
set.  This avoids running the verification loop for the first file, as
nothing has actually been merged at this point.  This significantly
increases performance for large config fragments.
Signed-off-by: NJosh Boyer <jwboyer@redhat.com>
Acked-by: NJohn Stultz <john.stultz@linaro.org>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

scripts/kconfig/merge_config.sh

@@ -58,12 +58,16 @@ while true; do
 	esac
 done
 
-
+INITFILE=$1
+shift;
 
 MERGE_LIST=$*
 SED_CONFIG_EXP="s/^\(# \)\{0,1\}\(CONFIG_[a-zA-Z0-9_]*\)[= ].*/\2/p"
 TMP_FILE=$(mktemp ./.tmp.config.XXXXXXXXXX)
 
+echo "Using $INITFILE as base"
+cat $INITFILE > $TMP_FILE
+
 # Merge files, printing warnings on overrided values
 for MERGE_FILE in $MERGE_LIST ; do
 	echo "Merging $MERGE_FILE"