bc: more fixes for unusual input bases

function                                             old     new   delta
zxc_program_num                                      990    1020     +30
zxc_lex_number                                       172     202     +30
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 60/0)               Total: 60 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/testsuite/bc_numbers2.bc b/testsuite/bc_numbers2.bc
new file mode 100644
index 0000000..208fe0d
--- /dev/null
+++ b/testsuite/bc_numbers2.bc
@@ -0,0 +1,18 @@
+define f() {
+	"ibase:";ibase
+	a=A;a
+	a=F;a
+	a=G;a
+	a=Z;a
+	a=0A;a
+	a=0F;a
+	a=0G;a
+	a=0Z;a
+}
+f()
+ibase=9;f()
+ibase=A;f()
+ibase=F;f()
+ibase=G;f()
+#ibase=Z;f()
+halt