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

win32/include/_mingw.h

@@ -139,6 +139,18 @@ typedef struct localeinfo_struct _locale_tstruct,*_locale_t;
 #define NOSERVICE 1
 #define NOMCX 1
 #define NOIME 1
+#define __INTRIN_H_
+#ifndef DUMMYUNIONNAME
+#  define DUMMYUNIONNAME
+#  define DUMMYUNIONNAME1
+#  define DUMMYUNIONNAME2
+#  define DUMMYUNIONNAME3
+#  define DUMMYUNIONNAME4
+#  define DUMMYUNIONNAME5
+#endif
+#ifndef DUMMYSTRUCTNAME
+#  define DUMMYSTRUCTNAME
+#endif
 #ifndef WINVER
 # define WINVER 0x0502
 #endif