config: use /bin/dash as CONFIG_SHELL if it's installed on the build host

This speeds up autotools configure and libtool quite a lot.

Signed-off-by: Matthias Reichl <hias@horus.com>

config/options

@@ -144,6 +144,11 @@ if [ "${OEM}" = "yes" -o "${OEM}" = "no" ]; then
   OEM_SUPPORT="${OEM}"
 fi
 
+# use /bin/dash as config shell if installed on the build host
+if [ -z "${CONFIG_SHELL}" ] && [ -x "/bin/dash" ]; then
+  export CONFIG_SHELL="/bin/dash"
+fi
+
 check_config
 
 . config/graphic

config/show_config

@@ -39,6 +39,7 @@ show_config() {
   config_message+="\n - CFLAGS:\t\t\t\t ${TARGET_CFLAGS}"
   config_message+="\n - LDFLAGS:\t\t\t\t $(sed 's/^ *//' <<< ${TARGET_LDFLAGS})"
   config_message+="\n - Local Ccache:\t\t\t ${LOCAL_CCACHE:-no}"
+  config_message+="\n - CONFIG_SHELL:\t\t\t ${CONFIG_SHELL:-auto}"
 
   # Misc. hardware configuration