i915c: Add a symlink for i830_dri.so

The gallium driver doesn't support gen2, so let's make it possible to
keep both i915g and i830 drivers installed in parallel.

Reviewed-by: Eric Anholt <eric@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10554>

src/loader/pci_id_driver_map.h

@@ -8,6 +8,12 @@
 #  error "Only include from loader.c"
 #endif
 
+static const int i830_chip_ids[] = {
+#define CHIPSET(chip, desc, name) chip,
+#include "pci_ids/i830_pci_ids.h"
+#undef CHIPSET
+};
+
 static const int i915_chip_ids[] = {
 #define CHIPSET(chip, desc, name) chip,
 #include "pci_ids/i915_pci_ids.h"
@@ -66,6 +72,7 @@ static const struct {
    int num_chips_ids;
    bool (*predicate)(int fd);
 } driver_map[] = {
+   { 0x8086, "i830", i830_chip_ids, ARRAY_SIZE(i830_chip_ids) },
    { 0x8086, "i915", i915_chip_ids, ARRAY_SIZE(i915_chip_ids) },
    { 0x8086, "i965", i965_chip_ids, ARRAY_SIZE(i965_chip_ids) },
    { 0x8086, "iris", NULL, -1, is_kernel_i915 },