bashism in Makefile.am

[eli-schwartz]

lrzip/lzma/C/Makefile.am

Lines 47 to 63 in 15f5621

	## hack to force asm compilation and to trick libtool with .lo file
	if USE_ASM
	liblzma_la_LIBADD = $(ASM_7z).lo
	7ZIPASMLOFILE := \
	\# $(ASM_7z).lo - a libtool object file\
	\n\# Generated by libtool -- hack to allow asm linking\
	\n\# Peter Hyman\
	\npic_object='.libs/$(ASM_7z).o'\
	\nnon_pic_object='$(ASM_7z).o'
	$(ASM_7z).lo: $(ASM_S)
	$(ASM_PROG) $(ASM_OPT) -o $(ASM_7z).o $(ASM_S)
	mkdir -p .libs
	cp $(ASM_7z).o .libs/
	@echo -e "$(7ZIPASMLOFILE)" > $(ASM_7z).lo
	endif

This uses echo -e which doesn't have predictable or reliable behavior e.g. when your /bin/sh is the dash shell rather than GNU Bash. The resulting libtool script ends up with an -e at the start of the file because -e isn't an option depending on the echo implementation.

There are some notes about reliability of the echo command at https://pubs.opengroup.org/onlinepubs/9699919799/utilities/echo.html including a warning that for reliability and robustness reasons one should always prefer to use printf unless echoing a string that doesn't begin with a dash and which contains no escape sequences whatsoever.

See e.g. https://bugs.gentoo.org/923990