sh-leading-hyphen.mk revision 1.4 
11.4Srillig# $NetBSD: sh-leading-hyphen.mk,v 1.4 2023/01/19 19:55:27 rillig Exp $
21.1Srillig#
31.2Srillig# Tests for shell commands preceded by a '-', to ignore the exit status of
41.2Srillig# the command line.
51.3Srillig#
61.3Srillig# See also:
71.3Srillig#	.IGNORE
81.3Srillig#	depsrc-ignore.mk
91.3Srillig#	opt-ignore.mk
101.1Srillig
111.1Srillig# TODO: Implementation
121.1Srillig
131.1Srilligall:
141.4Srillig	-true
151.4Srillig	-false
161.4Srillig
171.4Srillig	# An undefined variable expands to an empty string, without warning.
181.4Srillig	# This is used in practice for prefixing tool names or for DESTDIR.
191.4Srillig	# The '-' before 'unknown' is interpreted by make as '.IGNORE' flag.
201.4Srillig	${UNDEF}-unknown-command 'needed for needshell in compat.c'
211.4Srillig
221.4Srillig	# Expanding undefined variables may lead to strange error messages
231.4Srillig	# when the shell interprets single-character options as commands
241.4Srillig	# instead.
251.4Srillig	${UNDEF} --unknown-long-option 'needed for needshell in compat.c'
261.4Srillig
271.4Srillig	# Since 2023-01-17, the leading '@', '+' and '-' may contain
281.4Srillig	# whitespace, for compatibility with GNU make.
291.4Srillig	- - - @echo 'whitespace in leading part'
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