Fix deleting files with dependency files (#2045)

Makefile

@@ -315,10 +315,9 @@ else
 	@echo -e ".text\n\t.align\t2, 0\n" >> $3.s
 	$$(AS) $$(ASFLAGS) -o $$@ $3.s
 endif
+ifneq ($(NODEP),1)
 $1.d: $2
 	$(SCANINC) -M $1.d $(INCLUDE_SCANINC_ARGS) -I tools/agbcc/include $2
-ifneq ($(NODEP),1)
-$1.o: $1.d
 -include $1.d
 endif
 endef
@@ -346,7 +345,6 @@ endef
 
 define ASM_SCANINC
 ifneq ($(NODEP),1)
-$1.o: $1.d
 $1.d: $2
 	$(SCANINC) -M $1.d $(INCLUDE_SCANINC_ARGS) -I "" $2
 -include $1.d

tools/scaninc/scaninc.cpp

@@ -157,19 +157,29 @@ int main(int argc, char **argv)
         // Print a make rule for the object file
         size_t ext_pos = make_outfile.find_last_of(".");
         auto object_file = make_outfile.substr(0, ext_pos + 1) + "o";
-        output << object_file.c_str() << ": ";
+        output << object_file.c_str() << ":";
         for (const std::string &path : dependencies)
         {
-            output << path << " ";
+            output << " " << path;
         }
+        output << '\n';
 
         // Dependency list rule.
         // Although these rules are identical, they need to be separate, else make will trigger the rule again after the file is created for the first time.
-        output << "\n" << make_outfile.c_str() << ": ";
+        output << make_outfile.c_str() << ":";
         for (const std::string &path : dependencies_includes)
         {
-            output << path << " ";
+            output << " " << path;
         }
+        output << '\n';
+
+        // Dummy rules
+        // If a dependency is deleted, make will try to make it, instead of rescanning the dependencies before trying to do that.
+        for (const std::string &path : dependencies)
+        {
+            output << path << ":\n";
+        }
+
         output.flush();
         output.close();
     }