tcc: re-enable correct option -r support

Forgot about it.  It allows to compile several
sources (and other .o's) to one single .o file;

    tcc -r -o all.o f1.c f2.c f3.S o4.o ...

Also:
- option -fold-struct-init-code removed, no effect anymore
- (tcc_)set_environment() moved to tcc.c
- win32/lib/(win)crt1 minor fix & add dependency
- debug line output for asm (tcc -c -g xxx.S) enabled
- configure/Makefiles: x86-64 -> x86_64 changes
- README: cleanup

tcc-doc.texi

@@ -387,10 +387,10 @@ gcc's algorithm.
 Select the float ABI. Possible values: @code{softfp} and @code{hard}
 
 @item -mno-sse
-Do not use sse registers on x86-64
+Do not use sse registers on x86_64
 
 @item -m32, -m64
-Pass command line to the i386/x86-64 cross compiler.
+Pass command line to the i386/x86_64 cross compiler.
 
 @end table