[gimp] INSTALL: adding libwebp in optional dependency list.

[Jehan Pagès <jehanp src gnome org>]

commit 9e9cd496f73b857866999c01a8647632f4082a4d
Author: Jehan <jehan girinstud io>
Date:   Tue Aug 16 02:41:34 2016 +0200

    INSTALL: adding libwebp in optional dependency list.

 INSTALL.in |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/INSTALL.in b/INSTALL.in
index 4645642..03ea4bb 100644
--- a/INSTALL.in
+++ b/INSTALL.in
@@ -165,6 +165,7 @@ header files installed.
      libXcursor                -               X11 Mouse Cursor
      libxpm            -               XPM
      ExcHndl           -               Crash logs on Windows with Dr. MinGW
+     libwebp           @WEBP_REQUIRED_VERSION@         WebP
 
  19. Summary of optional runtime dependencies: