Zap toys/Config.in and instead create generated/Config.in from contents of
toys/*.c. Move relevant info into comment at the top of each toys/*.c. Also
convert more of Makefile into a thin wrapper around shell scripts that actually
do the work. (Makefile is only still there for the user interface.)
diff --git a/configure b/configure
new file mode 100644
index 0000000..c9990f2
--- /dev/null
+++ b/configure
@@ -0,0 +1,13 @@
+# Toybox configuration file.
+
+# This sets environment variables used by scripts/make.sh
+
+# A synonym.
+[ -z "$CROSS_COMPILE" ] && CROSS_COMPILE="$CROSS"
+
+[ -z "$CFLAGS" ] && CFLAGS="-Wall -Wundef -Wno-char-subscripts"
+CFLAGS="$CFLAGS -funsigned-char"
+[ -z "$OPTIMIZE" ] && OPTIMIZE="-Os -ffunction-sections -fdata-sections -Wl,--gc-sections"
+[ -z "$CC" ] && CC="${CROSS_COMPILE}gcc"
+[ -z "$STRIP" ] && STRIP="${CROSS_COMPILE}strip"
+[ -z "$HOSTCC" ] && HOSTCC=gcc