Build: support library and generator dependencies

Instead of directly manipulating LDFLAGS, set LIB_DEPS in each
subdirectory Makefile listing the libraries needed for
building/linking such as "LIB_DEPS = Core GUI Draw IPC Core".

This adds each library as an -L and -l argument in LDFLAGS, but
also adds the library.a file as a link dependency on the current
$(PROGRAM).  This causes the given library to be (re)built before
linking the current $(PROGRAM), but will also re-link any binaries
depending on that library when it is modified, when running make
from the root directory.

Also turn generator tools like IPCCompiler into dependencies on the
files they generate, so they are built on-demand when a particular
directory needs them.

This all allows the root Makefile to just list directories and not
care about the order, as all of the dependency tracking will figure
it out.

5 files changed, 41 insertions, 9 deletions

diff --git a/Libraries/LibAudio/Makefile b/Libraries/LibAudio/Makefile
index aad4b7122d..a7bda37485 100644
--- a/Libraries/LibAudio/Makefile
+++ b/Libraries/LibAudio/Makefile
@@ -4,6 +4,10 @@ OBJS = \
 
 LIBRARY = libaudio.a
 
+AClientConnection.cpp: ../../Servers/AudioServer/AudioClientEndpoint.h
+../../Servers/AudioServer/AudioClientEndpoint.h:
+	@$(MAKE) -C $(dir $(@))
+
 install:
 	mkdir -p $(SERENITY_BASE_DIR)/Root/usr/include/LibAudio/
 	cp *.h $(SERENITY_BASE_DIR)/Root/usr/include/LibAudio/
diff --git a/Libraries/LibC/Makefile b/Libraries/LibC/Makefile
index 522e5c545b..76b3832838 100644
--- a/Libraries/LibC/Makefile
+++ b/Libraries/LibC/Makefile
@@ -1,3 +1,5 @@
+.NOTPARALLEL:
+
 AK_OBJS = \
     ../../AK/StringImpl.o \
     ../../AK/String.o \
@@ -59,19 +61,22 @@ OBJS = $(AK_OBJS) $(LIBC_OBJS)
 
 EXTRA_OBJS = setjmp.ao crti.ao crtn.ao
 
-.PHONY: startfiles
-startfiles: $(EXTRA_OBJS)
-	$(CXX) $(CXXFLAGS) -o crt0.o -c crt0.cpp
+crt0.o: crt0.cpp
+	$(QUIET) $(CXX) $(CXXFLAGS) -o crt0.o -c crt0.cpp
+
+crtio.o: crti.ao
 	$(QUIET) cp crti.ao crti.o
+
+crtn.o: crtin.ao
 	$(QUIET) cp crtn.ao crtn.o
 
-EXTRA_CLEAN = crt0.d
+EXTRA_CLEAN = crt0.d crt0.o
 
 DEFINES = -DSERENITY_LIBC_BUILD
 
 LIBRARY = libc.a
 
-all: $(LIBRARY) startfiles install
+all: crt0.o $(EXTRA_OBJS) $(LIBRARY) install
 
 install:
 	mkdir -p $(SERENITY_BASE_DIR)/Root/usr/include/sys/
diff --git a/Libraries/LibGUI/Makefile b/Libraries/LibGUI/Makefile
index cc54c54b11..25f23cec2e 100644
--- a/Libraries/LibGUI/Makefile
+++ b/Libraries/LibGUI/Makefile
@@ -63,6 +63,11 @@ OBJS = \
 
 LIBRARY = libgui.a
 
+GWindowServerConnection.cpp: ../../Servers/WindowServer/WindowServerEndpoint.h
+
+../../Servers/WindowServer/WindowServerEndpoint.h:
+	@$(MAKE) -C $(dir $(@))
+
 install:
 	mkdir -p $(SERENITY_BASE_DIR)/Root/usr/include/LibGUI/
 	cp ./*.h $(SERENITY_BASE_DIR)/Root/usr/include/LibGUI/
diff --git a/Libraries/LibHTML/CodeGenerators/Makefile b/Libraries/LibHTML/CodeGenerators/Makefile
new file mode 100644
index 0000000000..29af0b03ea
--- /dev/null
+++ b/Libraries/LibHTML/CodeGenerators/Makefile
@@ -0,0 +1,3 @@
+SUBDIRS := $(wildcard */.)
+
+include ../../../Makefile.subdir
diff --git a/Libraries/LibHTML/Makefile b/Libraries/LibHTML/Makefile
index c0a1672c0c..1ff6b91919 100644
--- a/Libraries/LibHTML/Makefile
+++ b/Libraries/LibHTML/Makefile
@@ -67,17 +67,28 @@ EXTRA_SOURCES = \
     CSS/PropertyID.h \
     CSS/PropertyID.cpp
 
+GENERATE_CSS_PROPERTYID_CPP = CodeGenerators/Generate_CSS_PropertyID_cpp/Generate_CSS_PropertyID_cpp
+GENERATE_CSS_PROPERTYID_H = CodeGenerators/Generate_CSS_PropertyID_h/Generate_CSS_PropertyID_h
+
+$(GENERATE_CSS_PROPERTYID_H):
+	@$(MAKE) -C $(dir $(GENERATE_CSS_PROPERTYID_H))
+
+$(GENERATE_CSS_PROPERTYID_CPP):
+	@$(MAKE) -C $(dir $(GENERATE_CSS_PROPERTYID_CPP))
+
 CSS/DefaultStyleSheetSource.cpp: CSS/Default.css Scripts/GenerateStyleSheetSource.sh
 	@echo "GENERATE $@"
 	$(QUIET) Scripts/GenerateStyleSheetSource.sh default_stylesheet_source $< > $@
 
-CSS/PropertyID.h: CSS/Properties.json CodeGenerators/Generate_CSS_PropertyID_h/Generate_CSS_PropertyID_h.cpp
+CSS/PropertyID.h: CSS/Properties.json $(GENERATE_CSS_PROPERTYID_H)
 	@echo "GENERATE $@"
-	$(QUIET) CodeGenerators/Generate_CSS_PropertyID_h/Generate_CSS_PropertyID_h $< > $@
+	$(QUIET) $(GENERATE_CSS_PROPERTYID_H) $< > $@
 
-CSS/PropertyID.cpp: CSS/Properties.json CodeGenerators/Generate_CSS_PropertyID_cpp/Generate_CSS_PropertyID_cpp.cpp
+CSS/PropertyID.cpp: CSS/Properties.json $(GENERATE_CSS_PROPERTYID_CPP)
 	@echo "GENERATE $@"
-	$(QUIET) CodeGenerators/Generate_CSS_PropertyID_cpp/Generate_CSS_PropertyID_cpp $< > $@
+	$(QUIET) $(GENERATE_CSS_PROPERTYID_CPP) $< > $@
+
+EXTRA_CLEAN = CSS/DefaultStyleSheetSource.cpp CSS/PropertyID.h CSS/PropertyID.cpp
 
 OBJS = $(EXTRA_OBJS) $(LIBHTML_OBJS)
 
@@ -91,3 +102,7 @@ install:
 	cp $(LIBRARY) $(SERENITY_BASE_DIR)/Root/usr/lib/
 
 include ../../Makefile.common
+
+SUBDIRS = CodeGenerators
+
+include ../../Makefile.subdir