Better detect total failure of linker script generation.

ChangeLog

@@ -1,5 +1,8 @@
 2011-06-10  Roland McGrath  <roland@hack.frob.com>
 
+	* Makerules (shlib.lds): Fail if the linker script comes out empty.
+	* elf/Makefile ($(objpfx)ld.so): Likewise.
+
 	* Makefile ($(common-objpfx)linkobj/libc.so): Break long lines with \.
 	Don't list ld.so twice in dependencies.
 

Makerules

@@ -510,6 +510,7 @@ $(common-objpfx)shlib.lds: $(common-objpfx)config.make $(..)Makerules
 		 __libc_thread_subfreeres : { *(__libc_thread_subfreeres) }\
 		 PROVIDE(__stop___libc_thread_subfreeres = .);\
 		 /DISCARD/ : { *(.gnu.glibc-stub.*) }@'
+	test -s $@T
 	mv -f $@T $@
 common-generated += shlib.lds
 

elf/Makefile

@@ -413,6 +413,7 @@ $(objpfx)ld.so: $(objpfx)librtld.os $(ld-map)
 		  sed -e '/^=========/,/^=========/!d;/^=========/d'	\
 		      -e 's/\. = .* + SIZEOF_HEADERS;/& _begin = . - SIZEOF_HEADERS;/' \
 		  > $@.lds
+	test -s $@.lds
 	$(LINK.o) -nostdlib -nostartfiles -shared -o $@			\
 		  $(LDFLAGS-rtld) -Wl,-z,defs $(z-now-$(bind-now))	\
 		  $(filter-out $(map-file),$^) $(load-map-file)		\