Clear CFLAGS & LDFLAGS in tests

Clear CFLAGS and LDFLAGS to build the tests, in case the main Makefile
passes some flags that aren't handled by tcc (we are not compiling tcc
here, we are using tcc to compile the tests).

tests/Makefile

@@ -7,6 +7,10 @@ include $(TOP)/Makefile
 SRCDIR = $(top_srcdir)/tests
 VPATH = $(SRCDIR) $(top_srcdir)
 
+# clear CFLAGS and LDFLAGS
+CFLAGS :=
+LDFLAGS :=
+
 # what tests to run
 TESTS = \
  hello-exe \

tests/tests2/Makefile

@@ -1,6 +1,10 @@
 TOP = ../..
 include $(TOP)/Makefile
 
+# clear CFLAGS and LDFLAGS
+CFLAGS :=
+LDFLAGS :=
+
 ifdef CONFIG_WIN32
  TCCFLAGS = -B$(top_srcdir)/win32 -I$(top_srcdir)/include -L$(TOP)
 else