.cvsignore -> .gitignore

We no longer use CVS, so let's teach Git about what files to ignore...

... though doing `git status` after make + `make test` still gives
untracked content:

    # Untracked files:
    #   (use "git add <file>..." to include in what will be committed)
    #
    #       alloca86-bt.o
    #       alloca86.o
    #       bcheck.o
    #       libtcc.a
    #       libtcc.o
    #       libtcc1.a
    #       libtcc1.o
    #       tcc.o

See next patch about this stuff.

.gitignore

@@ -0,0 +1,37 @@
+tcc_g
+tcc
+tc2.c
+doc
+tc3s.c
+p3.c
+tc1.c
+error.c
+i386-gen1.c
+test.out2
+test.out3
+web.sh
+memdebug.c
+bench
+Makefile.uClibc
+boundtest
+prog.ref
+test.ref
+test.out
+tcc-doc.html
+ideas
+tcctest.ref
+linux.tcc
+ldtest
+libtcc_test
+instr.S
+p.c
+p2.c
+tcctest[1234]
+test[1234].out
+.gdb_history
+tcc.1
+tcc.pod
+config.h
+config.mak
+config.texi
+tests