FormCompiler: Build individual compilation units instead of all-at-a-time.

DevTools/FormCompiler/Makefile

@@ -1,28 +1,31 @@
 PROGRAM = FormCompiler
 
-SOURCES = \
-    main.cpp \
-    ../../AK/String.cpp \
-    ../../AK/StringImpl.cpp \
-    ../../AK/StringBuilder.cpp \
-    ../../AK/StringView.cpp \
-    ../../AK/JsonObject.cpp \
-    ../../AK/JsonValue.cpp \
-    ../../AK/JsonArray.cpp \
-    ../../AK/JsonParser.cpp \
-    ../../AK/LogStream.cpp \
-    ../../Libraries/LibCore/CIODevice.cpp \
-    ../../Libraries/LibCore/CFile.cpp \
-    ../../Libraries/LibCore/CObject.cpp \
-    ../../Libraries/LibCore/CEvent.cpp \
-    ../../Libraries/LibCore/CEventLoop.cpp
+OBJS = \
+    main.o \
+    ../../AK/String.o \
+    ../../AK/StringImpl.o \
+    ../../AK/StringBuilder.o \
+    ../../AK/StringView.o \
+    ../../AK/JsonObject.o \
+    ../../AK/JsonValue.o \
+    ../../AK/JsonArray.o \
+    ../../AK/JsonParser.o \
+    ../../AK/LogStream.o \
+    ../../Libraries/LibCore/CIODevice.o \
+    ../../Libraries/LibCore/CFile.o \
+    ../../Libraries/LibCore/CObject.o \
+    ../../Libraries/LibCore/CEvent.o \
+    ../../Libraries/LibCore/CEventLoop.o
 
 all: $(PROGRAM)
 
 CXXFLAGS = -std=c++17 -Wall -Wextra
 
-$(PROGRAM): $(SOURCES)
-	$(PRE_CXX) $(CXX) $(CXXFLAGS) -I../ -I../../ -I../../Libraries/ -o $@ $(SOURCES)
+%.o: %.cpp
+	$(PRE_CXX) $(CXX) $(CXXFLAGS) -I../ -I../../ -I../../Libraries/ -o $@ -c $<
+
+$(PROGRAM): $(OBJS)
+	$(CXX) $(LDFLAGS) -I../ -I../../ -I../../Libraries/ -o $(PROGRAM) $(OBJS)
 
 clean:
-	rm -f $(PROGRAM)
+	rm -f $(PROGRAM) $(OBJS)