* Makerules (check-abi-%): Use two rules for $(common-objpfx) and

$(objpfx) directories, and get rid of vpath directives.  The previous
	arrangement resulted in files being written to the source directories
	when run in a clean build.  Find all .abilist files in $(..)abilist/.
	(update-abi-%): Likewise.
	(generated): Don't add .symlist files, they'll be intermediates.

	* sysdeps/generic/init-first.c: Add a comment.

	* elf/Makefile ($(objpfx)ld.so): Pass -z defs in link.

	* scripts/gen-as-const.awk: Grok lone "--" as a separator between
	#includes and expressions.

	* scripts/merge-abilist.awk: Omit cpu-.*-os.*/modifier from merged
	config list when it already contains cpu-.*-os.* without / part.

	* Makerules (sed-remove-dotdot): New variable.
	($(common-objpfx)%.make): Use it.  Depend on $(before-compile).
	($(common-objpfx)%.h $(common-objpfx)%.h.d): Likewise.
	(check-abi-config): New variable, append /tls or /notls to the tuple.
	(check-abi-%): Use that for -v config value.
	Find .abilist files in abilist/libfoo.abilist, not in subdir.
	* Rules: Move bits/stdio_lim.h generation rules to Makerules.

scripts/gen-as-const.awk

@@ -17,6 +17,9 @@ NF >= 1 && !started {
   started = 1;
 }
 
+# Separator.
+$1 == "--" { next }
+
 NF == 1 { sub(/^.*$/, "& &"); }
 
 NF > 1 {