Check for and use gcc's -pipe.

Speeds up configure and build by a couple of percent.  ok djm@

configure.ac

@@ -179,6 +179,7 @@ AC_COMPILE_IFELSE([AC_LANG_SOURCE([[int main(void) { return 0; }]])],
 CFLAGS="$saved_CFLAGS"
 
 if test "$GCC" = "yes" || test "$GCC" = "egcs"; then
+	OSSH_CHECK_CFLAG_COMPILE([-pipe])
 	OSSH_CHECK_CFLAG_COMPILE([-Qunused-arguments])
 	OSSH_CHECK_CFLAG_COMPILE([-Wunknown-warning-option])
 	OSSH_CHECK_CFLAG_COMPILE([-Wall])