diff --git a/scripts/make.sh b/scripts/make.sh
index d3dc8eb..80d1484 100755
--- a/scripts/make.sh
+++ b/scripts/make.sh
@@ -27,7 +27,9 @@
 # Is anything under directory $2 newer than file $1
 isnewer()
 {
- [ ! -z "$(find "$2" -newer "$1" 2>/dev/null || echo yes)" ]
+  CHECK="$1"
+  shift
+  [ ! -z "$(find "$@" -newer "$CHECK" 2>/dev/null || echo yes)" ]
 }
 
 echo "Generate headers from toys/*/*.c..."
@@ -66,7 +68,8 @@
 TOYFILES="$(egrep -l "TOY[(]($TOYFILES)[ ,]" toys/*/*.c)"
 CFLAGS="$CFLAGS $(cat generated/cflags)"
 BUILD="$(echo ${CROSS_COMPILE}${CC} $CFLAGS -I . $OPTIMIZE $GITHASH)"
-FILES="$(echo lib/*.c main.c $TOYFILES)"
+LIBFILES="$(ls lib/*.c | grep -v lib/help.c)"
+TOYFILES="lib/help.c main.c $TOYFILES"
 
 if [ "${TOYFILES/pending//}" != "$TOYFILES" ]
 then
@@ -81,7 +84,7 @@
   echo
   echo "BUILD=\"$BUILD\""
   echo
-  echo "FILES=\"$FILES\""
+  echo "FILES=\"$LIBFILES $TOYFILES\""
   echo
   echo "LINK=\"$LINK\""
   echo
@@ -116,77 +119,88 @@
 LINK="$(echo $LDOPTIMIZE $LDFLAGS -o "$UNSTRIPPED" -Wl,--as-needed $(cat generated/optlibs.dat))"
 genbuildsh > generated/build.sh && chmod +x generated/build.sh || exit 1
 
-echo "Make generated/config.h from $KCONFIG_CONFIG."
+if isnewer generated/config.h "$KCONFIG_CONFIG"
+then
+  echo "Make generated/config.h from $KCONFIG_CONFIG."
 
-# This long and roundabout sed invocation is to make old versions of sed happy.
-# New ones have '\n' so can replace one line with two without all the branches
-# and tedious mucking about with hold space.
+  # This long and roundabout sed invocation is to make old versions of sed
+  # happy. New ones have '\n' so can replace one line with two without all
+  # the branches and tedious mucking about with hold space.
 
-sed -n \
-  -e 's/^# CONFIG_\(.*\) is not set.*/\1/' \
-  -e 't notset' \
-  -e 's/^CONFIG_\(.*\)=y.*/\1/' \
-  -e 't isset' \
-  -e 's/^CONFIG_\([^=]*\)=\(.*\)/#define CFG_\1 \2/p' \
-  -e 'd' \
-  -e ':notset' \
-  -e 'h' \
-  -e 's/.*/#define CFG_& 0/p' \
-  -e 'g' \
-  -e 's/.*/#define USE_&(...)/p' \
-  -e 'd' \
-  -e ':isset' \
-  -e 'h' \
-  -e 's/.*/#define CFG_& 1/p' \
-  -e 'g' \
-  -e 's/.*/#define USE_&(...) __VA_ARGS__/p' \
-  $KCONFIG_CONFIG > generated/config.h || exit 1
+  sed -n \
+    -e 's/^# CONFIG_\(.*\) is not set.*/\1/' \
+    -e 't notset' \
+    -e 's/^CONFIG_\(.*\)=y.*/\1/' \
+    -e 't isset' \
+    -e 's/^CONFIG_\([^=]*\)=\(.*\)/#define CFG_\1 \2/p' \
+    -e 'd' \
+    -e ':notset' \
+    -e 'h' \
+    -e 's/.*/#define CFG_& 0/p' \
+    -e 'g' \
+    -e 's/.*/#define USE_&(...)/p' \
+    -e 'd' \
+    -e ':isset' \
+    -e 'h' \
+    -e 's/.*/#define CFG_& 1/p' \
+    -e 'g' \
+    -e 's/.*/#define USE_&(...) __VA_ARGS__/p' \
+    $KCONFIG_CONFIG > generated/config.h || exit 1
+fi
 
 if [ generated/mkflags -ot scripts/mkflags.c ]
 then
   do_loudly $HOSTCC scripts/mkflags.c -o generated/mkflags || exit 1
 fi
 
-echo -n "generated/flags.h "
-
 # Process config.h and newtoys.h to generate FLAG_x macros. Note we must
 # always #define the relevant macro, even when it's disabled, because we
 # allow multiple NEWTOY() in the same C file. (When disabled the FLAG is 0,
 # so flags&0 becomes a constant 0 allowing dead code elimination.)
 
-# Parse files through C preprocessor twice, once to get flags for current
-# .config and once to get flags for allyesconfig
-for I in A B
-do
-  (
-  # define macros and select header files with option string data
+make_flagsh()
+{
+  # Parse files through C preprocessor twice, once to get flags for current
+  # .config and once to get flags for allyesconfig
+  for I in A B
+  do
+    (
+    # define macros and select header files with option string data
 
-  echo "#define NEWTOY(aa,bb,cc) aa $I bb"
-  echo '#define OLDTOY(...)'
-  if [ "$I" == A ]
-  then
-    cat generated/config.h
-  else
-    sed '/USE_.*([^)]*)$/s/$/ __VA_ARGS__/' generated/config.h
-  fi
-  cat generated/newtoys.h
+    echo "#define NEWTOY(aa,bb,cc) aa $I bb"
+    echo '#define OLDTOY(...)'
+    if [ "$I" == A ]
+    then
+      cat generated/config.h
+    else
+      sed '/USE_.*([^)]*)$/s/$/ __VA_ARGS__/' generated/config.h
+    fi
+    cat generated/newtoys.h
 
-  # Run result through preprocessor, glue together " " gaps leftover from USE
-  # macros, delete comment lines, print any line with a quoted optstring,
-  # turn any non-quoted opstring (NULL or 0) into " " (because fscanf can't
-  # handle "" with nothing in it, and mkflags uses that).
+    # Run result through preprocessor, glue together " " gaps leftover from USE
+    # macros, delete comment lines, print any line with a quoted optstring,
+    # turn any non-quoted opstring (NULL or 0) into " " (because fscanf can't
+    # handle "" with nothing in it, and mkflags uses that).
 
-  ) | ${CROSS_COMPILE}${CC} -E - | \
+    ) | ${CROSS_COMPILE}${CC} -E - | \
     sed -n -e 's/" *"//g;/^#/d;t clear;:clear;s/"/"/p;t;s/\( [AB] \).*/\1 " "/p'
 
-# Sort resulting line pairs and glue them together into triplets of
-#   command "flags" "allflags"
-# to feed into mkflags C program that outputs actual flag macros
-# If no pair (because command's disabled in config), use " " for flags
-# so allflags can define the appropriate zero macros.
+  # Sort resulting line pairs and glue them together into triplets of
+  #   command "flags" "allflags"
+  # to feed into mkflags C program that outputs actual flag macros
+  # If no pair (because command's disabled in config), use " " for flags
+  # so allflags can define the appropriate zero macros.
 
-done | sort -s | sed -n 's/ A / /;t pair;h;s/\([^ ]*\).*/\1 " "/;x;b single;:pair;h;n;:single;s/[^ ]* B //;H;g;s/\n/ /;p' | tee generated/flags.raw | \
-generated/mkflags > generated/flags.h || exit 1
+  done | sort -s | sed -n -e 's/ A / /;t pair;h;s/\([^ ]*\).*/\1 " "/;x' \
+    -e 'b single;:pair;h;n;:single;s/[^ ]* B //;H;g;s/\n/ /;p' | \
+    tee generated/flags.raw | generated/mkflags > generated/flags.h || exit 1
+}
+
+if isnewer generated/flags.h toys "$KCONFIG_CONFIG"
+then
+  echo -n "generated/flags.h "
+  make_flagsh
+fi
 
 # Extract global structure definitions and flag definitions from toys/*/*.c
 
@@ -230,13 +244,16 @@
     toys/*/*.c lib/*.c | generated/mktags > generated/tags.h
 fi
 
-echo "generated/help.h"
 if [ generated/config2help -ot scripts/config2help.c ]
 then
   do_loudly $HOSTCC scripts/config2help.c -I . lib/xwrap.c lib/llist.c \
     lib/lib.c lib/portability.c -o generated/config2help || exit 1
 fi
-generated/config2help Config.in $KCONFIG_CONFIG > generated/help.h || exit 1
+if isnewer generated/help.h generated/Config.in
+then
+  echo "generated/help.h"
+  generated/config2help Config.in $KCONFIG_CONFIG > generated/help.h || exit 1
+fi
 
 [ ! -z "$NOBUILD" ] && exit 0
 
@@ -246,26 +263,38 @@
 
 # This is a parallel version of: do_loudly $BUILD $FILES $LINK || exit 1
 
+# Any headers newer than the oldest generated/obj file?
 X="$(ls -1t generated/obj/* 2>/dev/null | tail -n 1)"
+# TODO: redo this
 if [ ! -e "$X" ] || [ ! -z "$(find toys -name "*.h" -newer "$X")" ]
 then
   rm -rf generated/obj && mkdir -p generated/obj || exit 1
 else
   rm -f generated/obj/{main,lib_help}.o || exit 1
 fi
+
+# build each generated/obj/*.o file in parallel
+
 PENDING=
-LFILES=
+LNKFILES=
 DONE=0
 COUNT=0
-for i in $FILES
+CLICK=
+
+for i in $LIBFILES click $TOYFILES
 do
-  # build each generated/obj/*.o file in parallel
+  [ "$i" == click ] && CLICK=1 && continue
 
   X=${i/lib\//lib_}
   X=${X##*/}
   OUT="generated/obj/${X%%.c}.o"
-  LFILES="$LFILES $OUT"
-  [ "$OUT" -nt "$i" ] && continue
+  LNKFILES="$LNKFILES $OUT"
+
+  # $LIBFILES doesn't need to be rebuilt if newer than .config, $TOYFILES does
+
+  [ "$OUT" -nt "$i" ] && [ -z "$CLICK" -o "$OUT" -nt "$KCONFIG_CONFIG" ] &&
+    continue
+
   do_loudly $BUILD -c $i -o $OUT &
   PENDING="$PENDING $!"
   COUNT=$(($COUNT+1))
@@ -294,7 +323,7 @@
 
 [ $DONE -ne 0 ] && exit 1
 
-do_loudly $BUILD $LFILES $LINK || exit 1
+do_loudly $BUILD $LNKFILES $LINK || exit 1
 if [ ! -z "$NOSTRIP" ] ||
   ! do_loudly ${CROSS_COMPILE}strip "$UNSTRIPPED" -o "$OUTNAME"
 then