intel: Add a INTEL_DEBUG=color option.

This will be used for color output in debug messages.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>

docs/envvars.html

@@ -160,6 +160,7 @@ See the <a href="xlibdriver.html">Xlib software driver page</a> for details.
    This is useful for debugging hangs, etc.</li>
 <li>INTEL_DEBUG - a comma-separated list of named flags, which do various things:
 <ul>
+   <li>color - use color in output</li>
    <li>tex - emit messages about textures.</li>
    <li>state - emit messages about state flag tracking</li>
    <li>blit - emit messages about blit operations</li>

src/intel/common/gen_debug.c

@@ -83,6 +83,7 @@ static const struct debug_control debug_control[] = {
    { "do32",        DEBUG_DO32 },
    { "norbc",       DEBUG_NO_RBC },
    { "nohiz",       DEBUG_NO_HIZ },
+   { "color",       DEBUG_COLOR },
    { NULL,    0 }
 };
 

src/intel/common/gen_debug.h

@@ -79,6 +79,7 @@ extern uint64_t INTEL_DEBUG;
 #define DEBUG_DO32                (1ull << 37)
 #define DEBUG_NO_RBC              (1ull << 38)
 #define DEBUG_NO_HIZ              (1ull << 39)
+#define DEBUG_COLOR               (1ull << 40)
 
 #ifdef HAVE_ANDROID_PLATFORM
 #define LOG_TAG "INTEL-MESA"