1# $NetBSD: recursive.mk,v 1.6 2023/06/01 20:56:35 rillig Exp $ 2# 3# In -dL mode, a variable may get expanded before it makes sense. 4# This would stop make from doing anything since the "recursive" error 5# is fatal and exits immediately. 6# 7# The purpose of evaluating that variable early was just to detect 8# whether there are unclosed variables. The variable value is therefore 9# parsed with VARE_PARSE_ONLY for that purpose. 10# 11# Seen in pkgsrc/x11/libXfixes, and probably many more package that use 12# GNU Automake. 13 14.MAKEFLAGS: -dL 15 16AM_V_lt= ${am__v_lt_${V}} 17am__v_lt_= ${am__v_lt_${AM_DEFAULT_VERBOSITY}} 18am__v_lt_0= --silent 19am__v_lt_1= 20 21# On 2020-08-06, make reported: "Variable am__v_lt_ is recursive." 22libXfixes_la_LINK= ... ${AM_V_lt} ... 23 24# somewhere later ... 25AM_DEFAULT_VERBOSITY= 1 26 27 28# The purpose of the -dL flag is to detect unclosed variables. This 29# can be achieved by just parsing the variable and not evaluating it. 30# 31# When the variable is only parsed but not evaluated, bugs in nested 32# variables are not discovered. But these are hard to produce anyway, 33# therefore that's acceptable. In most practical cases, the missing 34# brace would be detected directly in the line where it is produced. 35MISSING_BRACE_INDIRECT:= ${:U\${MISSING_BRACE} 36# expect+1: Unclosed variable "MISSING_PAREN" 37UNCLOSED= $(MISSING_PAREN 38# expect+1: Unclosed variable "MISSING_BRACE" 39UNCLOSED= ${MISSING_BRACE 40UNCLOSED= ${MISSING_BRACE_INDIRECT} 41