Adds test coverage with gcov & lcov ++

Makefile.am

@@ -1,5 +1,4 @@
 bin_PROGRAMS = asmsh child
-noinst_LIBRARIES = libcheck_asmsh.a
 
 libcheck_asmsh_a_SOURCES = mmap_parse.c asm_env.c compile.c logger.c
 
@@ -8,8 +7,32 @@ child_SOURCES = child.s
 
 SUBDIRS = 
 if CHECK
+noinst_LIBRARIES = libcheck_asmsh.a
+libcheck_asmsh_a_CFLAGS = @CFLAGS@ -fprofile-arcs -ftest-coverage
 SUBDIRS += tests
+
+LCOV_INFO=lcov.info
+LCOV_HTML=lcov_html
+
+checks: check coverage
+
+coverage: $(LCOV_HTML)
+
+$(LCOV_INFO): gcov
+	lcov --capture --directory . --output-file $@
+
+$(LCOV_HTML): $(LCOV_INFO)
+	genhtml $< --output-directory $@
+
+gcov: *.gcno
+	gcov -j $^
+
+clean-local:
+	-rm -rf *.gcov *.gcda *.gcno $(LCOV_INFO) $(LCOV_HTML)
+
 endif
 
 child$(EXEEXT): $(child_SOURCES:.s=.o)
 	ld $(child_LDFLAGS) -o $@ $<
+
+