It's clear that this change causes too many problems to be made
without warning. Revert the change disallowing conditional lines to
start with TAB.
Instead, generate warnings whenever a directive line begins with a
TAB character. Make this change for all directives, not just
conditional directives: define, undefine, export, unexport, vpath,
load, include, etc.
* NEWS: Update the backward-compatibility warning.
* src/read.c (eval): Track whether the line starts with a TAB.
If so then whenever we recognize a directive, emit a warning.
Revert the previous change for this bug.
(parse_var_assignment): Accept a file location if the line begins
with TAB; show a warning if we discover a directive.
(conditional_line): Warn about lines starting with TAB.
* tests/scripts/...: Add tests to verify warnings for initial TAB.
Avoid Emacs local variable settings to disable whitespace cleanup,
by creating markup tokens for TAB characters (#TAB#) and space
characters (#SPACE#) (for end-of-line spaces). Modify all the
tests that use TABs to use the new markup. This requires changing
some old-fashioned tests to use the modern run_make_test(). Also
remove some of the comments regarding test numbers now that the
framework keeps track.
POSIX Issue 8 will require a new assignment operator, :::=.
This operator behaves similarly to the BSD make := operator: the
right-hand side is expanded immediately, but then the value is
re-escaped (all '$' are converted to '$$') and the resulting variable
is considered a recursive variable: the value is re-expanded on use.
* src/variable.h (enum variable_flavor): Add f_expand flavor.
* src/variable.c (do_variable_definition): When defining f_expand,
post-process the result to re-escape '$' characters.
Remove default: to the compiler warns about un-handled enum values.
Set recursive values for both f_recursive and f_expand.
(parse_variable_definition): Rewrite this method.
The previous version was annoying to extend to ':::='.
(print_variable): Remove default: so the compiler warns us about
un-handled enum values.
* src/function.c (func_origin): Remove default: so the compiler warns
us about un-handled enum values.
* doc/make.texi: Add documentation for :::=.
* tests/scripts/variables/define: Add a test for define :::=.
* tests/scripts/variables/flavors: Add tests for :::=.
* tests/scripts/variables/negative: Add tests for :::=.
* src/read.c (parse_var_assignment): If called in a target-specific
variable context don't allow define/undefine as variable assignments.
* test/scripts/variables/define: Add a test.
* test/scripts/variables/undefine: Add a test.
