TT#111150 Simplify and improve build system

- Use built-in rules whenever possible.
- Split between optional and required options in flag variables.
- Refactor tests into a variable.

Change-Id: I1f82648c8b9757fc98acbcc1d8d7157a83f4ec79

asn1/Makefile.compiled

@@ -2,7 +2,8 @@
 
 LIBNAME=libtcap-asn.a
 
-CFLAGS+=-g -Wall -O3 -fPIC
+CFLAGS = -g -Wall -O3
+CFLAGS += -fPIC
 
 lib: $(LIBNAME)
 

src/Makefile

@@ -1,6 +1,10 @@
 CC=gcc
-CFLAGS+=-I../asn1-compiled -I../include -g -Wall -O3 -fPIC
-LDFLAGS=-O3 -shared -fPIC -Wl,-soname,$(LIBNAME).so.$(VERSION)
+
+CPPFLAGS += -I../asn1-compiled -I../include
+CFLAGS := -g -Wall -O3
+CFLAGS += -fPIC
+LDFLAGS := -O3
+LDFLAGS += -shared -fPIC -Wl,-soname,$(LIBNAME).so.$(VERSION)
 
 OBJS=tcap.o
 
@@ -11,7 +15,7 @@ OBJS=tcap.o
 all: $(LIBSO)
 
 $(LIBSOVER): $(OBJS) ../asn1-compiled/libtcap-asn.a
-	$(CC) -o $@ $(OBJS) ../asn1-compiled/libtcap-asn.a $(LDFLAGS)
+	$(CC) $(CFLAGS) -o $@ $(OBJS) ../asn1-compiled/libtcap-asn.a $(LDFLAGS)
 
 $(LIBSO): $(LIBSOVER)
 	ln -fs $(LIBSOVER) $(LIBSO)

tests/Makefile

@@ -1,12 +1,13 @@
 .PHONY: all clean
 
-all: basic encode
+CPPFLAGS += -I ../include -I../asn1-compiled
+CFLAGS := -Wall -g
+LDFLAGS += -L../src
+LDLIBS += -ltcap
 
-basic: basic.c ../src/libtcap.so.0
-	gcc -Wall -g -I ../include -I../asn1-compiled basic.c -o basic -L../src -ltcap
+TESTS = basic encode
 
-encode: encode.c ../src/libtcap.so.0
-	gcc -Wall -g -I ../include -I../asn1-compiled encode.c -o encode -L../src -ltcap
+all: $(TESTS)
 
 clean:
-	rm -f basic encode
+	rm -f $(TESTS)