shells: do not frocibly enable test, echo and kill _applets_,

just build relevant source and use xxx_main functions.
build system: add a special case when we have exactly one applet enabled
(makes "true", "false", "basename" REALLY tiny).
getopt32: do not use stdio.

function                                             old     new   delta
getopt32                                            1385    1412     +27
make_device                                         1187    1200     +13
basename_main                                        120     127      +7
tcpudpsvd_main                                      1922    1926      +4
testcmd                                                5       -      -5
echocmd                                                5       -      -5
fuser_main                                          1243    1231     -12
------------------------------------------------------------------------------
(add/remove: 0/2 grow/shrink: 4/1 up/down: 51/-22)             Total: 29 bytes

1 files changed, 3 insertions, 0 deletions

diff --git a/coreutils/Kbuild b/coreutils/Kbuild
index b9ed0d79e..253eb6da8 100644
--- a/coreutils/Kbuild
+++ b/coreutils/Kbuild
@@ -30,6 +30,7 @@ lib-$(CONFIG_DOS2UNIX)  += dos2unix.o
 lib-$(CONFIG_DU)        += du.o
 lib-$(CONFIG_ECHO)      += echo.o
 lib-$(CONFIG_ASH)       += echo.o # used by ash
+lib-$(CONFIG_HUSH)      += echo.o # used by hush
 lib-$(CONFIG_ENV)       += env.o
 lib-$(CONFIG_EXPR)      += expr.o
 lib-$(CONFIG_EXPAND)    += expand.o
@@ -72,6 +73,8 @@ lib-$(CONFIG_TAIL)      += tail.o
 lib-$(CONFIG_TEE)       += tee.o
 lib-$(CONFIG_TEST)      += test.o
 lib-$(CONFIG_ASH)       += test.o # used by ash
+lib-$(CONFIG_HUSH)      += test.o # used by hush
+lib-$(CONFIG_MSH)       += test.o # used by msh
 lib-$(CONFIG_TOUCH)     += touch.o
 lib-$(CONFIG_TR)        += tr.o
 lib-$(CONFIG_TRUE)      += true.o