win32/Makefile ("for cygwin") removed
- On cygwin, the normal ./configure && make can be used with either
  cygwin's "GCC for Win32 Toolchain"
      ./configure --cross-prefix=i686-w64-mingw32-
  or with an existing tcc:
      ./configure --cc=<old-tccdir>/tcc.exe

tcctest.c:
- exclude test_high_clobbers() on _WIN64 (does not work)

tests2/95_bitfield.c:
- use 'signed char' for ARM (where default 'char' is unsigned)

tests:
- remove -I "expr" diff option to allow tests with
  busybox-diff.

libtcc.c, tcc.c:
- removed -iwithprefix option.  It is supposed to be
  combined with -iprefix which we don't have either.

tccgen.c:
- fix assignments and return of 'void', as in
     void f() {
         void *p, *q;
         *p = *q:
         return *p;
     }
  This appears to be allowed but should do nothing.

tcc.h, libtcc.c, tccpp.c:
- Revert "Introduce VIP sysinclude paths which are always searched first"
  This reverts commit 1d5e386b0a78393ac6b670c209a185849ec798a1.

  The patch was giving tcc's system includes priority over -I which
  is not how it should be.

tccelf.c:
- add DT_TEXTREL tag only if text relocations are actually
  used (which is likely not the case on x86_64)
- prepare_dynamic_rel(): avoid relocation of unresolved
  (weak) symbols

tccrun.c:
- for HAVE_SELINUX, use two mappings to the same (real) file.
  (it was so once except the RX mapping wasn't used at all).

tccpe.c:
- fix relocation constant used for x86_64 (by Andrei E. Warentin)
- #ifndef _WIN32 do "chmod 755 ..." to get runnable exes on cygwin.

tccasm.c:
- keep forward asm labels static, otherwise they will endup
  in dynsym eventually.

configure, Makefile:
- mingw32: respect ./configure options --bindir --docdir --libdir
- allow overriding tcc when building libtcc1.a and libtcc.def with
      make XTCC=<tcc program to use>
- use $(wildcard ...) for install to allow installing just
  a cross compiler for example
      make cross-arm
      make install
- use name <target>-libtcc1.a

build-tcc.bat:
- add  options: -clean, -b bindir

Comments only, no change to functionality

Also:
- regenerate all tests/pp/*.expect with gcc
- test "insert one space" feature
- test "0x1E-1" in asm mode case
- PARSE_FLAG_SPACES: ignore \f\v\r better
- tcc.h: move some things

Insert a space when it is required to prevent mistokenisation of
the output, and also in a few cases where it is not strictly
required, imitating GCC's behaviour.

    * correct -E output for the case ++ + ++ concatenation
        do this only for expanded from macro string
        and only when tcc_state->output_type == TCC_OUTPUT_PREPROCESS