--- a/auto/fmt/fmt
+++ b/auto/fmt/fmt
@@ -1,22 +1,27 @@
 
-echo "Checking for $NGX_TYPE printf() format"
+echo "checking for $NGX_TYPE printf() format"
 
 NGX_FMT=NO
 
 for FMT in $NGX_FORMATS
 do
-    echo "#include <unistd.h>" > autotest.c
     echo "#include <stdio.h>" >> autotest.c
     echo "#include <sys/types.h>" >> autotest.c
     echo "int main() {" >> autotest.c
     echo "printf(\"${FMT}\", ($NGX_TYPE) $NGX_MAX_SIZE);" >> autotest.c
     echo "return 0; }" >> autotest.c
 
-    eval "${CC_WARN} -o autotest autotest.c > /dev/null 2>&1"
+    eval "$CC_WARN $CC_TEST_FLAGS -o autotest autotest.c > /dev/null 2>&1"
+
+    MAX_SIZE=`echo $NGX_MAX_SIZE | sed -e "s/L*\$//"`
 
     if [ -x ./autotest ]; then
-        if [ "`./autotest`" = $NGX_MAX_SIZE ]; then
-            echo " + \"${FMT}\" used"
+        if [ "`./autotest`" = $MAX_SIZE ]; then
+            if [ $NGX_FMT_COLLECT = YES ]; then
+                echo " + \"${FMT}\" is appropriate"
+            else
+                echo " + \"${FMT}\" used"
+            fi
             NGX_FMT=$FMT
         fi
     fi
@@ -24,7 +29,12 @@ do
     rm autotest*
 
     if [ $NGX_FMT != NO ]; then
-        break
+        if [ $NGX_FMT_COLLECT = YES ]; then
+            eval "NGX_${NGX_BYTES}_FMT=\"\${NGX_${NGX_BYTES}_FMT} \$NGX_FMT\""
+            continue
+        else
+            break
+        fi
     fi
 
     echo " + \"${FMT}\" is not appropriate"
@@ -32,12 +42,14 @@ done
 
 
 if [ $NGX_FMT = NO ]; then
-    echo "printf() $NGX_TYPE format not found"
+    echo "$0: error: printf() $NGX_TYPE format not found"
     exit 1
 fi
 
 
-echo "#ifndef $NGX_FMT_NAME"                 >> $NGX_AUTO_CONFIG_H
-echo "#define $NGX_FMT_NAME  \"$NGX_FMT\""   >> $NGX_AUTO_CONFIG_H
-echo "#endif"                                >> $NGX_AUTO_CONFIG_H
-echo                                         >> $NGX_AUTO_CONFIG_H
+if [ $NGX_FMT_COLLECT = NO ]; then
+    echo "#ifndef $NGX_FMT_NAME"                 >> $NGX_AUTO_CONFIG_H
+    echo "#define $NGX_FMT_NAME  \"$NGX_FMT\""   >> $NGX_AUTO_CONFIG_H
+    echo "#endif"                                >> $NGX_AUTO_CONFIG_H
+    echo                                         >> $NGX_AUTO_CONFIG_H
+fi