# $NetBSD: recursive.mk,v 1.5 2021/03/15 12:15:03 rillig Exp $ # # In -dL mode, a variable may get expanded before it makes sense. # This would stop make from doing anything since the "recursive" error # is fatal and exits immediately. # # The purpose of evaluating that variable early was just to detect # whether there are unclosed variables. The variable value is therefore # parsed with VARE_PARSE_ONLY for that purpose. # # Seen in pkgsrc/x11/libXfixes, and probably many more package that use # GNU Automake. .MAKEFLAGS: -dL AM_V_lt= ${am__v_lt_${V}} am__v_lt_= ${am__v_lt_${AM_DEFAULT_VERBOSITY}} am__v_lt_0= --silent am__v_lt_1= # On 2020-08-06, make reported: "Variable am__v_lt_ is recursive." libXfixes_la_LINK= ... ${AM_V_lt} ... # somewhere later ... AM_DEFAULT_VERBOSITY= 1 # The purpose of the -dL flag is to detect unclosed variables. This # can be achieved by just parsing the variable and not evaluating it. # # When the variable is only parsed but not evaluated, bugs in nested # variables are not discovered. But these are hard to produce anyway, # therefore that's acceptable. In most practical cases, the missing # brace would be detected directly in the line where it is produced. MISSING_BRACE_INDIRECT:= ${:U\${MISSING_BRACE} UNCLOSED= $(MISSING_PAREN UNCLOSED= ${MISSING_BRACE UNCLOSED= ${MISSING_BRACE_INDIRECT}