Issue 28017: Use -std=gnu99 to get C99 with GNU extensions for bluetooth.h on big endian.
diff --git a/configure b/configure
index 0be0850..4590423 100755
--- a/configure
+++ b/configure
@@ -6858,7 +6858,9 @@
 # tweak BASECFLAGS based on compiler and platform
 case $GCC in
 yes)
-    CFLAGS_NODIST="$CFLAGS_NODIST -std=c99"
+    # GNU dialect of C99, enables GNU extensions like __attribute__. GNU99
+    # is required by bluetooth.h on big endian machines.
+    CFLAGS_NODIST="$CFLAGS_NODIST -std=gnu99"
 
     # Python doesn't violate C99 aliasing rules, but older versions of
     # GCC produce warnings for legal Python code.  Enable