[gimp] INSTALL: libwebp must be built with --enable-libwebpmux...

[Jehan Pagès <jehanp src gnome org>]

commit 7725f1dc0e296539eb192528c257f1c6547a25f9
Author: Jehan <jehan girinstud io>
Date:   Tue Aug 16 21:04:58 2016 +0200

    INSTALL: libwebp must be built with --enable-libwebpmux...
    
    ... and --enable-libwebpdemux.

 INSTALL.in |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/INSTALL.in b/INSTALL.in
index 03ea4bb..6fc8f25 100644
--- a/INSTALL.in
+++ b/INSTALL.in
@@ -165,7 +165,7 @@ header files installed.
      libXcursor                -               X11 Mouse Cursor
      libxpm            -               XPM
      ExcHndl           -               Crash logs on Windows with Dr. MinGW
-     libwebp           @WEBP_REQUIRED_VERSION@         WebP
+     libwebp           @WEBP_REQUIRED_VERSION@         WebP (built with --enable-libwebpmux and 
--enable-libwebpdemux)
 
  19. Summary of optional runtime dependencies: