doublestatic: fix dependencies if two files depend on one non-generated file.

If a and b both depend on c, and c is a static (non-generated) file that has
changed since the last successful build of a and b, we would try to redo
a, but would forget to redo b.  Now it does both.

builder.py

@@ -64,18 +64,18 @@ class BuildJob:
             # important to prevent infinite recursion.  For example, a rule
             # called default.c.do could be used to try to produce hello.c,
             # which is undesirable since hello.c existed already.
-            state.stamp(t)
+            state.stamp_and_maybe_built(t)
             return self._after2(0)
         state.start(t)
         (dofile, basename, ext) = _find_do_file(t)
         if not dofile:
             if os.path.exists(t):
-                state.stamp(t)
+                state.stamp_and_maybe_built(t)
                 return self._after2(0)
             else:
                 err('no rule to make %r\n' % t)
                 return self._after2(1)
-        state.stamp(dofile)
+        state.stamp_and_maybe_built(dofile)
         unlink(tmpname)
         ffd = os.open(tmpname, os.O_CREAT|os.O_RDWR|os.O_EXCL, 0666)
         close_on_exec(ffd, True)

state.py

@@ -127,6 +127,14 @@ def isbuilt(t):
         return True
 
 
+# stamps the given input file, but only considers it to have been "built" if its
+# mtime has changed.  This is useful for static (non-generated) files.
+def stamp_and_maybe_built(t):
+    if stamped(t) != os.stat(t).st_mtime:
+        built(t)
+    stamp(t)
+
+        
 def mark(t):
     try:
         open(_sname('mark', t), 'w').close()

t/deps/.gitignore

@@ -3,4 +3,5 @@ t2.count
 overwrite
 overwrite[123]
 genfile2
-genfile.log
+genfile.log
+static.log

t/deps/clean.do

@@ -1,4 +1,3 @@
 redo basic/clean dirtest/clean
-rm -f *~ .*~ *.count t1a overwrite overwrite[123] genfile2 genfile.log
+rm -f *~ .*~ *.count t1a overwrite overwrite[123] \
-
+	genfile2 genfile.log static.log
-

t/deps/doublestatic.do

@@ -0,0 +1,10 @@
+rm -f static.log
+
+redo static1 static2
+
+touch static.in
+. ../flush-cache.sh
+redo-ifchange static1 static2
+
+COUNT=$(wc -l <static.log)
+[ "$COUNT" = 4 ] || exit 55

t/deps/static1.do

@@ -0,0 +1,2 @@
+redo-ifchange static.in
+echo $$ >>static.log

t/deps/static2.do

@@ -0,0 +1,2 @@
+redo-ifchange static.in
+echo $$ >>static.log

t/deps/test.do

@@ -1 +1,2 @@
-redo test1 test2 ifchange-fail overwrite gentest basic/test dirtest/test
+redo test1 test2 ifchange-fail overwrite gentest doublestatic \
+	basic/test dirtest/test