diff --git a/AK/Tests/Makefile b/AK/Tests/Makefile
index bd8ec67b83a..1d517b8cd4c 100644
--- a/AK/Tests/Makefile
+++ b/AK/Tests/Makefile
@@ -35,7 +35,6 @@ SHARED_TEST_OBJS = \
 
 define execute-command
 $(1)
-
 endef
 
 all: $(PROGRAMS)
diff --git a/Applications/Browser/Makefile b/Applications/Browser/Makefile
index a67bc091c90..e4843ac8cb0 100755
--- a/Applications/Browser/Makefile
+++ b/Applications/Browser/Makefile
@@ -7,10 +7,10 @@ LIB_DEPS = GUI HTML Draw IPC Protocol Core
 
 main.cpp: ../../Libraries/LibHTML/CSS/PropertyID.h
 ../../Libraries/LibHTML/CSS/PropertyID.h:
-	@$(MAKE) -C ../../Libraries/LibHTML
+	@flock ../../Libraries/LibHTML $(MAKE) -C ../../Libraries/LibHTML
 
 main.cpp: ../../Servers/ProtocolServer/ProtocolClientEndpoint.h
 ../../Servers/ProtocolServer/ProtocolClientEndpoint.h:
-	@$(MAKE) -C $(dir $(@))
+	@flock ../../Servers/ProtocolServer $(MAKE) -C $(dir $(@))
 
 include ../../Makefile.common
diff --git a/Libraries/LibAudio/Makefile b/Libraries/LibAudio/Makefile
index a7bda37485e..ae2ec668ad6 100644
--- a/Libraries/LibAudio/Makefile
+++ b/Libraries/LibAudio/Makefile
@@ -6,7 +6,7 @@ LIBRARY = libaudio.a
 
 AClientConnection.cpp: ../../Servers/AudioServer/AudioClientEndpoint.h
 ../../Servers/AudioServer/AudioClientEndpoint.h:
-	@$(MAKE) -C $(dir $(@))
+	@flock $(dir $(@)) $(MAKE) -C $(dir $(@))
 
 install:
 	mkdir -p $(SERENITY_BASE_DIR)/Root/usr/include/LibAudio/
diff --git a/Libraries/LibC/Makefile b/Libraries/LibC/Makefile
index 76b38328386..ee3996b7bae 100644
--- a/Libraries/LibC/Makefile
+++ b/Libraries/LibC/Makefile
@@ -1,5 +1,3 @@
-.NOTPARALLEL:
-
 AK_OBJS = \
     ../../AK/StringImpl.o \
     ../../AK/String.o \
@@ -62,7 +60,6 @@ OBJS = $(AK_OBJS) $(LIBC_OBJS)
 EXTRA_OBJS = setjmp.ao crti.ao crtn.ao
 
 crt0.o: crt0.cpp
-	$(QUIET) $(CXX) $(CXXFLAGS) -o crt0.o -c crt0.cpp
 
 crtio.o: crti.ao
 	$(QUIET) cp crti.ao crti.o
@@ -76,7 +73,9 @@ DEFINES = -DSERENITY_LIBC_BUILD
 
 LIBRARY = libc.a
 
-all: crt0.o $(EXTRA_OBJS) $(LIBRARY) install
+POST_LIBRARY_BUILD = $(QUIET) $(MAKE) install
+
+all: crt0.o $(EXTRA_OBJS) $(LIBRARY)
 
 install:
 	mkdir -p $(SERENITY_BASE_DIR)/Root/usr/include/sys/
diff --git a/Libraries/LibGUI/Makefile b/Libraries/LibGUI/Makefile
index 25f23cec2e4..7d71bf950aa 100644
--- a/Libraries/LibGUI/Makefile
+++ b/Libraries/LibGUI/Makefile
@@ -66,7 +66,7 @@ LIBRARY = libgui.a
 GWindowServerConnection.cpp: ../../Servers/WindowServer/WindowServerEndpoint.h
 
 ../../Servers/WindowServer/WindowServerEndpoint.h:
-	@$(MAKE) -C $(dir $(@))
+	@flock $(dir $(@)) $(MAKE) -C $(dir $(@))
 
 install:
 	mkdir -p $(SERENITY_BASE_DIR)/Root/usr/include/LibGUI/
diff --git a/Libraries/LibHTML/Makefile b/Libraries/LibHTML/Makefile
index 1ff6b91919f..6ce339aedb0 100644
--- a/Libraries/LibHTML/Makefile
+++ b/Libraries/LibHTML/Makefile
@@ -71,10 +71,10 @@ GENERATE_CSS_PROPERTYID_CPP = CodeGenerators/Generate_CSS_PropertyID_cpp/Generat
 GENERATE_CSS_PROPERTYID_H = CodeGenerators/Generate_CSS_PropertyID_h/Generate_CSS_PropertyID_h
 
 $(GENERATE_CSS_PROPERTYID_H):
-	@$(MAKE) -C $(dir $(GENERATE_CSS_PROPERTYID_H))
+	@flock $(dir $(GENERATE_CSS_PROPERTYID_H)) $(MAKE) -C $(dir $(GENERATE_CSS_PROPERTYID_H))
 
 $(GENERATE_CSS_PROPERTYID_CPP):
-	@$(MAKE) -C $(dir $(GENERATE_CSS_PROPERTYID_CPP))
+	@flock $(dir $(GENERATE_CSS_PROPERTYID_CPP)) $(MAKE) -C $(dir $(GENERATE_CSS_PROPERTYID_CPP))
 
 CSS/DefaultStyleSheetSource.cpp: CSS/Default.css Scripts/GenerateStyleSheetSource.sh
 	@echo "GENERATE $@"
@@ -82,11 +82,11 @@ CSS/DefaultStyleSheetSource.cpp: CSS/Default.css Scripts/GenerateStyleSheetSourc
 
 CSS/PropertyID.h: CSS/Properties.json $(GENERATE_CSS_PROPERTYID_H)
 	@echo "GENERATE $@"
-	$(QUIET) $(GENERATE_CSS_PROPERTYID_H) $< > $@
+	$(QUIET) flock CSS $(GENERATE_CSS_PROPERTYID_H) $< > $@
 
 CSS/PropertyID.cpp: CSS/Properties.json $(GENERATE_CSS_PROPERTYID_CPP)
 	@echo "GENERATE $@"
-	$(QUIET) $(GENERATE_CSS_PROPERTYID_CPP) $< > $@
+	$(QUIET) flock CSS $(GENERATE_CSS_PROPERTYID_CPP) $< > $@
 
 EXTRA_CLEAN = CSS/DefaultStyleSheetSource.cpp CSS/PropertyID.h CSS/PropertyID.cpp
 
diff --git a/Libraries/LibProtocol/Makefile b/Libraries/LibProtocol/Makefile
index fb5732a68df..3521c20a001 100644
--- a/Libraries/LibProtocol/Makefile
+++ b/Libraries/LibProtocol/Makefile
@@ -6,6 +6,6 @@ LIBRARY = libprotocol.a
 
 Download.cpp: ../../Servers/ProtocolServer/ProtocolClientEndpoint.h
 ../../Servers/ProtocolServer/ProtocolClientEndpoint.h:
-	@$(MAKE) -C $(dir $(@))
+	@flock $(dir $(@)) $(MAKE) -C $(dir $(@))
 
 include ../../Makefile.common
diff --git a/Makefile b/Makefile
index 8ab4e9408b1..31e79296d0d 100644
--- a/Makefile
+++ b/Makefile
@@ -23,6 +23,6 @@ ifeq ($(UNAME_S),Darwin)
 test: 
 else
 test:
-	$(QUIET) $(MAKE) -C AK/Tests clean all clean
+	$(QUIET) flock AK/Tests $(MAKE) -C AK/Tests clean all clean
 endif
 
diff --git a/Makefile.common b/Makefile.common
index 45ff9671170..203bd090fbd 100644
--- a/Makefile.common
+++ b/Makefile.common
@@ -103,19 +103,21 @@ $(PROGRAM): $(STATIC_LIB_DEPS) $(SUFFIXED_OBJS) $(EXTRA_OBJS)
 $(LIBRARY): $(SUFFIXED_OBJS) $(EXTRA_OBJS)
 	@echo "LIB $@"
 	$(QUIET) $(AR) rcs $@ $(OBJS) $(EXTRA_OBJS) $(LIBS)
+	$(POST_LIBRARY_BUILD)
 
+#.PHONY: $(STATIC_LIB_DEPS)
 $(STATIC_LIB_DEPS):
-	@$(MAKE) -C $(dir $(@))
+	@flock $(dir $(@)) $(MAKE) -C $(dir $(@))
 
 IPCCOMPILER = $(SERENITY_BASE_DIR)/DevTools/IPCCompiler/IPCCompiler
 IPCCOMPILER: $(IPCCOMPILER)
 $(IPCCOMPILER):
-	@$(MAKE) -C $(dir $(@))
+	@flock $(dir $(@)) $(MAKE) -C $(dir $(@))
 
 FORMCOMPILER = $(SERENITY_BASE_DIR)/DevTools/FormCompiler/FormCompiler
 FORMCOMPILER: $(FORMCOMPILER)
 $(FORMCOMPILER):
-	@$(MAKE) -C $(dir $(@))
+	@flock $(dir $(@)) $(MAKE) -C $(dir $(@))
 
 .DEFAULT_GOAL := all
 
diff --git a/Makefile.subdir b/Makefile.subdir
index b4e86913f8c..f7f0e0cd076 100644
--- a/Makefile.subdir
+++ b/Makefile.subdir
@@ -1,17 +1,17 @@
 subdirs: $(SUBDIRS)
 $(SUBDIRS):
-	@$(MAKE) -C $@
+	@flock $@ $(MAKE) -C $@
 
 all: $(subdirs)
 
 SUBDIRS_CLEAN = $(addsuffix .clean,$(SUBDIRS))
 clean: $(SUBDIRS_CLEAN)
 $(SUBDIRS_CLEAN): %.clean:
-	@$(MAKE) -C $* clean
+	@flock $* $(MAKE) -C $* clean
 
 SUBDIRS_INSTALL = $(addsuffix .install,$(SUBDIRS))
 install: $(SUBDIRS_INSTALL)
 $(SUBDIRS_INSTALL): %.install:
-	@$(MAKE) -C $* install
+	@flock $* $(MAKE) -C $* install
 
 .PHONY: all clean install $(SUBDIRS)