Using disk file to store large request body.

This closes #386 on GitHub.

auto/help

@@ -20,6 +20,7 @@ cat << END
   --incdir=DIRECTORY   set includes directory name, default: "$NXT_INCDIR"
   --modules=DIRECTORY  set modules directory name, default: "$NXT_MODULES"
   --state=DIRECTORY    set state directory name, default: "$NXT_STATE"
+  --tmp=DIRECTORY      set tmp directory name, default: "$NXT_TMP"
 
   --pid=FILE           set pid filename, default: "$NXT_PID"
   --log=FILE           set log filename, default: "$NXT_LOG"

auto/options

@@ -58,6 +58,7 @@ do
         --incdir=*)                      NXT_INCDIR="$value"                 ;;
         --modules=*)                     NXT_MODULES="$value"                ;;
         --state=*)                       NXT_STATE="$value"                  ;;
+        --tmp=*)                         NXT_TMP="$value"                    ;;
 
         --pid=*)                         NXT_PID="$value"                    ;;
         --log=*)                         NXT_LOG="$value"                    ;;
@@ -149,6 +150,11 @@ case "$NXT_STATE" in
      *)  NXT_STATE="$NXT_PREFIX$NXT_STATE"  ;;
 esac
 
+case "$NXT_TMP" in
+    /*)  ;;
+     *)  NXT_TMP="$NXT_PREFIX$NXT_TMP"  ;;
+esac
+
 case "$NXT_PID" in
     /*)  ;;
      *)  NXT_PID="$NXT_PREFIX$NXT_PID"  ;;

auto/save

@@ -29,5 +29,6 @@ NXT_LIB_AUX_LIBS=
 NXT_LIB_UNIT_STATIC='$NXT_LIB_UNIT_STATIC'
 
 NXT_MODULES='$NXT_MODULES'
+NXT_TMP='$NXT_TMP'
 
 END

auto/summary

@@ -13,6 +13,7 @@ Unit configuration summary:
   include directory: ......... "$NXT_INCDIR"
   modules directory: ......... "$NXT_MODULES"
   state directory: ........... "$NXT_STATE"
+  tmp directory: ............. "$NXT_TMP"
 
   pid file: .................. "$NXT_PID"
   log file: .................. "$NXT_LOG"