maint: disable GNU indent checks for now

GNU indent will reformat a bunch of files in a way that's broken or
incorrect, so disable the check until we can find a way to workaround
this.  Unfortunately, the indent check is enforced at `make distcheck`
time if GNU indent is installed, so it can't simply be ignored.

* cfg.mk (local-checks-to-skip): Add sc_indent.

cfg.mk

@@ -55,6 +55,7 @@ local-checks-to-skip =				\
 	$(local-checks-to-fix)			\
 	sc_GPL_version				\
 	sc_cast_of_x_alloc_return_value		\
+	sc_indent				\
 	sc_prohibit_always-defined_macros	\
 	sc_prohibit_always_true_header_tests	\
 	sc_prohibit_strncpy			\