misc: fix nm 'No such file' error

Reset CSRC-y to prevent pollution from libc/misc/glob/Makefile.in, and fix the
following error messages when UCLIBC_HAS_OBSTACK is disabled:

nm: 'libc/misc/gnu/glob-susv3.os': No such file
nm: 'libc/misc/gnu/glob64-susv3.os': No such file

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

libc/misc/gnu/Makefile.in

@@ -7,6 +7,7 @@
 
 subdirs += libc/misc/gnu
 
+CSRC-y :=
 CSRC-$(UCLIBC_HAS_OBSTACK) := obstack.c obprintf.c
 
 MISC_GNU_DIR := $(top_srcdir)libc/misc/gnu