[babl] babl: return the linear TRC when 1.0 is asked for numerically

[Øyvind Kolås <ok src gnome org>]

commit f2581d9c6730f182907699ec3fda5970dd4dd8af
Author: Øyvind Kolås <pippin gimp org>
Date:   Sat Aug 19 03:53:16 2017 +0200

    babl: return the linear TRC when 1.0 is asked for numerically

 babl/babl-trc.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/babl/babl-trc.c b/babl/babl-trc.c
index c1bc107..9f8cb58 100644
--- a/babl/babl-trc.c
+++ b/babl/babl-trc.c
@@ -89,6 +89,8 @@ babl_trc_gamma (double gamma)
 {
   char name[32];
   int i;
+  if (fabs (gamma - 1.0) < 0.0001)
+     return babl_trc_new ("linear", BABL_TRC_LINEAR, 1.0);
   sprintf (name, "%.6f", gamma);
   for (i = 0; name[i]; i++)
     if (name[i] == ',') name[i] = '.';