build: Fix 'make -j' handling.

Some build targets create multiple outputs, which can cause problems
when doing parallel builds. Clean up the build system so that all
subdir invocations come from the top-level Makefile and use $(MAKE).
Also fix the FREEDOOM/FREEDM lumps to really include the version
number by using $(shell ...) syntax.

lumps/textures/Makefile

@@ -1,13 +1,9 @@
 
 CPP=../../scripts/simplecpp
-PHASE1_OUTPUTS = phase1/texture1.lmp phase1/texture2.lmp \
-                 phase1/pnames.lmp
-PHASE2_OUTPUTS = phase2/texture1.lmp phase2/pnames.lmp
-FREEDM_OUTPUTS = freedm/texture1.lmp freedm/pnames.lmp
 
-all: $(PHASE1_OUTPUTS) $(PHASE2_OUTPUTS) $(FREEDM_OUTPUTS)
+all: phase1/texture1.lmp phase2/texture1.lmp freedm/texture1.lmp
 
-$(PHASE1_OUTPUTS): textures.cfg
+phase1/texture1.lmp:
 	$(CPP) -DDOOM1 -DULTDOOM < textures.cfg |                \
 	./build-textures -compat_texture1=doom1/texture1.txt     \
 	                 -compat_texture2=doom1/texture2.txt     \
@@ -16,14 +12,14 @@ $(PHASE1_OUTPUTS): textures.cfg
 			 -output_texture2=phase1/texture2.lmp    \
 			 -output_pnames=phase1/pnames.lmp
 
-$(PHASE2_OUTPUTS): textures.cfg
+phase2/texture1.lmp:
 	$(CPP) -DDOOM1 -DDOOM2 < textures.cfg |                  \
 	./build-textures -compat_texture1=doom2/texture1.txt     \
 			 -compat_pnames=doom2/pnames.txt         \
 			 -output_texture1=phase2/texture1.lmp    \
 			 -output_pnames=phase2/pnames.lmp
 
-$(FREEDM_OUTPUTS): textures.cfg
+freedm/texture1.lmp:
 	$(CPP) -DDOOM1 -DDOOM2 -DFREEDM < textures.cfg |         \
 	./build-textures -compat_texture1=doom2/texture1.txt     \
 			 -compat_pnames=doom2/pnames.txt         \
@@ -32,5 +28,7 @@ $(FREEDM_OUTPUTS): textures.cfg
 
 
 clean:
-	rm -f $(PHASE1_OUTPUTS) $(PHASE2_OUTPUTS) $(FREEDM_OUTPUTS)
+	rm -f phase1/texture1.lmp phase1/texture2.lmp phase1/pnames.lmp \
+	      phase2/texture1.lmp phase2/pnames.lmp                     \
+	      freedm/texture1.lmp freedm/pnames.lmp