Make second expansion optional (partial implementation).

I decided this feature was too impacting to make the permanent default
behavior.  This set of changes makes the default behavior of make the
old behavior (no second expansion).  If you want second expansion, you
must define the .SECONDEXPANSION: special target before the first target
that needs it.

This set of changes ONLY fixes explicit and static pattern rules to work
like this.  Implicit rules still have second expansion enabled all the
time: I'll work on that next.

Note that there is still a backward-incompatibility: now to get the old
SysV behavior using $$@ etc. in the prerequisites list you need to set
.SECONDEXPANSION: as well.

1 files changed, 16 insertions, 9 deletions

diff --git a/tests/scripts/misc/general4 b/tests/scripts/misc/general4
index 63320e2..0b5c94a 100644
--- a/tests/scripts/misc/general4
+++ b/tests/scripts/misc/general4
@@ -5,8 +5,7 @@ This tests random features of make's algorithms, often somewhat obscure,
 which have either broken at some point in the past or seem likely to
 break.";
 
-open(MAKEFILE,"> $makefile");
-print MAKEFILE <<'EOF';
+run_make_test('
 # Make sure that subdirectories built as prerequisites are actually handled
 # properly.
 
@@ -16,13 +15,8 @@ dir/subdir: ; @echo mkdir -p dir/subdir
 
 dir/subdir/file.b: dir/subdir ; @echo touch dir/subdir/file.b
 
-dir/subdir/%.a: dir/subdir/%.b ; @echo cp $< $@
-EOF
-close(MAKEFILE);
-
-&run_make_with_options($makefile,"",&get_logfile);
-$answer = "mkdir -p dir/subdir\ntouch dir/subdir/file.b\ncp dir/subdir/file.b dir/subdir/file.a\n";
-&compare_output($answer,&get_logfile(1));
+dir/subdir/%.a: dir/subdir/%.b ; @echo cp $< $@',
+              '', "mkdir -p dir/subdir\ntouch dir/subdir/file.b\ncp dir/subdir/file.b dir/subdir/file.a\n");
 
 # Test implicit rules
 
@@ -47,4 +41,17 @@ fox: baz
               'done bar');
 unlink('bar');
 
+
+# Test implicit rules with '$' in the name (see se_implicit)
+
+run_make_test(q!
+%.foo : baz$$bar ; @echo 'done $<'
+%.foo : bar$$baz ; @echo 'done $<'
+test.foo:
+fox: baz
+.DEFAULT baz$$bar bar$$baz: ; @echo '$@'
+!,
+              '',
+              'done bar');
+
 1;