Fix compiler warning in qcms with gcc/arm

third_party/qcms/src/transform.c

 /* vim: set ts=8 sw=8 noexpandtab: */
 //  qcms
 //  Copyright (C) 2009 Mozilla Corporation
 //  Copyright (C) 1998-2007 Marti Maria
 //
 // Permission is hereby granted, free of charge, to any person obtaining 
 // a copy of this software and associated documentation files (the "Software"), 
 // to deal in the Software without restriction, including without limitation 
 // the rights to use, copy, modify, merge, publish, distribute, sublicense, 
 // and/or sell copies of the Software, and to permit persons to whom the Software 
@@ skipping 1305 matching lines @@
                         }
                 }
         } else {
                 assert(0 && "unexpected colorspace");
                 transform_free(transform);
                 return NULL;
         }
         return transform;
 }
 
-#if defined(__GNUC__) && !defined(__x86_64__) && !defined(__amd64__)
-#if !defined(__has_attribute)
-/* Assume that the compiler supports the provided attribute. */
-#define __has_attribute(x) 1
+/* __force_align_arg_pointer__ is an x86-only attribute, and gcc/clang warns on unused
+ * attributes. Don't use this on ARM or AMD64. __has_attribute can detect the presence
+ * of the attribute but is currently only supported by clang */
+#if defined(__has_attribute)
+#define HAS_FORCE_ALIGN_ARG_POINTER __has_attribute(__force_align_arg_pointer__)
+#elif defined(__GNUC__) && !defined(__x86_64__) && !defined(__amd64__) && !defined(__arm__)
+#define HAS_FORCE_ALIGN_ARG_POINTER 1
+#else
+#define HAS_FORCE_ALIGN_ARG_POINTER 0
 #endif
-#if __has_attribute(__force_align_arg_pointer__)
+
+#if HAS_FORCE_ALIGN_ARG_POINTER
 /* we need this to avoid crashes when gcc assumes the stack is 128bit aligned */
 __attribute__((__force_align_arg_pointer__))
-#else
-/* __force_align_arg_pointer__ is an x86-only attribute, and clang warns on used
- * attributes. Don't use this on ARM.
- */
-#endif
 #endif
 void qcms_transform_data(qcms_transform *transform, void *src, void *dest, size_t length)
 {
         static const struct _qcms_format_type output_rgbx = { 0, 2 };
 
         transform->transform_fn(transform, src, dest, length, output_rgbx);
 }
 
 void qcms_transform_data_type(qcms_transform *transform, void *src, void *dest, size_t length, qcms_output_type type)
 {
         static const struct _qcms_format_type output_rgbx = { 0, 2 };
         static const struct _qcms_format_type output_bgrx = { 2, 0 };
 
         transform->transform_fn(transform, src, dest, length, type == QCMS_OUTPUT_BGRX ? output_bgrx : output_rgbx);
 }
 
 qcms_bool qcms_supports_iccv4;
 void qcms_enable_iccv4()
 {
         qcms_supports_iccv4 = true;
 }