Refine selection of the default programmer

If neither internal (old default) nor dummy (safe default) programmer
are selected, we must pick a sensible default programmer.

Since there is no reason to prefer a particular external programmer,
we abort compilation if more than one of them is selected. If only one
is selected, it is clear that the user wants that one to become the
default. This fixes single-programmer compilation.

Corresponding to flashrom svn r858.
Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Sean Nelson <audiohacked@gmail.com>

flashrom.c

@@ -39,8 +39,37 @@ enum programmer programmer = PROGRAMMER_INTERNAL;
 #elif DUMMY_SUPPORT == 1
 enum programmer programmer = PROGRAMMER_DUMMY;
 #else
-/* Activating the #error explodes on make dep. */
-//#error Neither internal nor dummy selected
+/* If neither internal nor dummy are selected, we must pick a sensible default.
+ * Since there is no reason to prefer a particular external programmer, we fail
+ * if more than one of them is selected. If only one is selected, it is clear
+ * that the user wants that one to become the default.
+ */
+#if NIC3COM_SUPPORT+GFXNVIDIA_SUPPORT+DRKAISER_SUPPORT+SATASII_SUPPORT+FT2232_SPI_SUPPORT+SERPROG_SUPPORT+BUSPIRATE_SPI_SUPPORT > 1
+#error Please enable either CONFIG_DUMMY or CONFIG_INTERNAL or disable support for all external programmers except one.
+#endif
+enum programmer programmer =
+#if NIC3COM_SUPPORT == 1
+	PROGRAMMER_NIC3COM
+#endif
+#if GFXNVIDIA_SUPPORT == 1
+	PROGRAMMER_GFXNVIDIA
+#endif
+#if DRKAISER_SUPPORT == 1
+	PROGRAMMER_DRKAISER
+#endif
+#if SATASII_SUPPORT == 1
+	PROGRAMMER_SATASII
+#endif
+#if FT2232_SPI_SUPPORT == 1
+	PROGRAMMER_FT2232SPI
+#endif
+#if SERPROG_SUPPORT == 1
+	PROGRAMMER_SERPROG
+#endif
+#if BUSPIRATE_SPI_SUPPORT == 1
+	PROGRAMMER_BUSPIRATESPI
+#endif
+;
 #endif
 
 char *programmer_param = NULL;