[babl/wip/msvc: 4/20] extensions/gegl-fixups.c: Don't assume GCC

[Chun-wei Fan <fanchunwei src gnome org>]

commit ed9e57bf80faf3985493e554eb241b46f6221b58
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Mon Jan 20 16:09:12 2020 +0800

    extensions/gegl-fixups.c: Don't assume GCC
    
    Instead, define a macro in babl/babl-macros./h that is defined to
    __attribute__((unused)) on GCC and to nothing on non-GCC, and make use of it.

 babl/babl-macros.h       | 6 ++++++
 extensions/gegl-fixups.c | 8 ++++----
 2 files changed, 10 insertions(+), 4 deletions(-)
---
diff --git a/babl/babl-macros.h b/babl/babl-macros.h
index 010d97f7d..a286e6373 100644
--- a/babl/babl-macros.h
+++ b/babl/babl-macros.h
@@ -30,4 +30,10 @@
 #define BABL_ARG_NULL_TERMINATED
 #endif
 
+#ifdef  __GNUC__
+#define BABL_GNUC_ATTRIBUTE_UNUSED __attribute__((unused))
+#else
+#define BABL_GNUC_ATTRIBUTE_UNUSED
 #endif
+
+#endif /* _BABL_MACROS_H */
diff --git a/extensions/gegl-fixups.c b/extensions/gegl-fixups.c
index 45888ce65..589b57cf0 100644
--- a/extensions/gegl-fixups.c
+++ b/extensions/gegl-fixups.c
@@ -183,7 +183,7 @@ conv_F_8g (const Babl    *conversion,
 }
 
 
-static inline void __attribute__((unused))
+static inline void BABL_GNUC_ATTRIBUTE_UNUSED
 conv_8_F (const Babl    *conversion,
           unsigned char *src, 
           unsigned char *dst, 
@@ -232,7 +232,7 @@ conv_rgbaF_rgb8 (const Babl    *conversion,
 }
 
 
-static void __attribute__((unused))
+static void BABL_GNUC_ATTRIBUTE_UNUSED
 conv_rgbaF_rgba8 (const Babl    *conversion,
                   unsigned char *src, 
                   unsigned char *dst, 
@@ -266,7 +266,7 @@ conv_rgbaF_rgba8 (const Babl    *conversion,
 
 #define conv_rgbaF_rgbP8    conv_rgbaF_rgba8
 
-static void __attribute__((unused))
+static void BABL_GNUC_ATTRIBUTE_UNUSED
 conv_rgbF_rgb8 (const Babl    *conversion,
                 unsigned char *src, 
                 unsigned char *dst, 
@@ -275,7 +275,7 @@ conv_rgbF_rgb8 (const Babl    *conversion,
   conv_F_8g (conversion, src, dst, samples * 3);
 }
 
-static void __attribute__((unused))
+static void BABL_GNUC_ATTRIBUTE_UNUSED
 conv_gaF_ga8 (const Babl    *conversion,
               unsigned char *src, 
               unsigned char *dst,