SSI: avoid potential buffer overflow. When "-" follows a parameter of maximum length, a single byte buffer overflow happens, since the error branch does not check parameter length. Fix is to avoid saving "-" to the parameter key, and instead use an error message with "-" explicitly written. The message is mostly identical to one used in similar cases in the preequal state. Reported by Patrick Wollgast.

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


    cat << END                                            >> $NGX_MAKEFILE

$NGX_LIBATOMIC/src/libatomic_ops.a:	$NGX_LIBATOMIC/Makefile
	cd $NGX_LIBATOMIC && \$(MAKE)

$NGX_LIBATOMIC/Makefile:	$NGX_MAKEFILE
	cd $NGX_LIBATOMIC \\
	&& if [ -f Makefile ]; then \$(MAKE) distclean; fi \\
	&& ./configure

END