cygwin.h

gcc-you can use this code to learn something about gcc, and inquire further into linux,

}

/* Don't allow flag_pic to propagate since gas may produce invalid code
   otherwise.  */

#undef  SUBTARGET_OVERRIDE_OPTIONS
#define SUBTARGET_OVERRIDE_OPTIONS					\
do {									\
  if (flag_pic)								\
    {									\
      warning ("-f%s ignored for target (all code is position independent)",\
	       (flag_pic > 1) ? "PIC" : "pic");				\
      flag_pic = 0;							\
    }									\
} while (0)								\

/* Define this macro if references to a symbol must be treated
   differently depending on something about the variable or
   function named by the symbol (such as what section it is in).

   On i386 running Windows NT, modify the assembler name with a suffix 
   consisting of an atsign (@) followed by string of digits that represents
   the number of bytes of arguments passed to the function, if it has the 
   attribute STDCALL.

   In addition, we must mark dll symbols specially. Definitions of 
   dllexport'd objects install some info in the .drectve section.  
   References to dllimport'd objects are fetched indirectly via
   _imp__.  If both are declared, dllexport overrides.  This is also 
   needed to implement one-only vtables: they go into their own
   section and we need to set DECL_SECTION_NAME so we do that here.
   Note that we can be called twice on the same decl.  */

#undef TARGET_ENCODE_SECTION_INFO
#define TARGET_ENCODE_SECTION_INFO  i386_pe_encode_section_info
#undef  TARGET_STRIP_NAME_ENCODING
#define TARGET_STRIP_NAME_ENCODING  i386_pe_strip_name_encoding_full

/* Output a reference to a label.  */
#undef ASM_OUTPUT_LABELREF
#define ASM_OUTPUT_LABELREF(STREAM, NAME)  		\
  fprintf (STREAM, "%s%s", USER_LABEL_PREFIX, 		\
	   i386_pe_strip_name_encoding (NAME))		\

/* Output a common block.  */
#undef ASM_OUTPUT_COMMON
#define ASM_OUTPUT_COMMON(STREAM, NAME, SIZE, ROUNDED)	\
do {							\
  if (i386_pe_dllexport_name_p (NAME))			\
    i386_pe_record_exported_symbol (NAME, 1);		\
  if (! i386_pe_dllimport_name_p (NAME))		\
    {							\
      fprintf ((STREAM), "\t.comm\t"); 			\
      assemble_name ((STREAM), (NAME));			\
      fprintf ((STREAM), ", %d\t%s %d\n",		\
	       (ROUNDED), ASM_COMMENT_START, (SIZE));	\
    }							\
} while (0)

/* Output the label for an initialized variable.  */
#undef ASM_DECLARE_OBJECT_NAME
#define ASM_DECLARE_OBJECT_NAME(STREAM, NAME, DECL) 	\
do {							\
  if (i386_pe_dllexport_name_p (NAME))			\
    i386_pe_record_exported_symbol (NAME, 1);		\
  ASM_OUTPUT_LABEL ((STREAM), (NAME));			\
} while (0)


/* Emit code to check the stack when allocating more that 4000
   bytes in one go.  */

#define CHECK_STACK_LIMIT 4000

/* By default, target has a 80387, uses IEEE compatible arithmetic,
   returns float values in the 387 and needs stack probes.
   We also align doubles to 64-bits for MSVC default compatibility. */

#undef TARGET_SUBTARGET_DEFAULT
#define TARGET_SUBTARGET_DEFAULT \
   (MASK_80387 | MASK_IEEE_FP | MASK_FLOAT_RETURNS | MASK_STACK_PROBE \
    | MASK_ALIGN_DOUBLE)

/* This is how to output an assembler line
   that says to advance the location counter
   to a multiple of 2**LOG bytes.  */

#undef ASM_OUTPUT_ALIGN
#define ASM_OUTPUT_ALIGN(FILE,LOG)	\
    if ((LOG)!=0) fprintf ((FILE), "\t.align %d\n", 1<<(LOG))

/* Define this macro if in some cases global symbols from one translation
   unit may not be bound to undefined symbols in another translation unit
   without user intervention.  For instance, under Microsoft Windows
   symbols must be explicitly imported from shared libraries (DLLs).  */
#define MULTIPLE_SYMBOL_SPACES

extern void i386_pe_unique_section PARAMS ((TREE, int));
#define TARGET_ASM_UNIQUE_SECTION i386_pe_unique_section

#define SUPPORTS_ONE_ONLY 1

/* Switch into a generic section.  */
#define TARGET_ASM_NAMED_SECTION  i386_pe_asm_named_section

/* Select attributes for named sections.  */
#define TARGET_SECTION_TYPE_FLAGS  i386_pe_section_type_flags

/* Write the extra assembler code needed to declare a function
   properly.  If we are generating SDB debugging information, this
   will happen automatically, so we only need to handle other cases.  */
#undef ASM_DECLARE_FUNCTION_NAME
#define ASM_DECLARE_FUNCTION_NAME(FILE, NAME, DECL)			\
  do									\
    {									\
      if (i386_pe_dllexport_name_p (NAME))				\
	i386_pe_record_exported_symbol (NAME, 0);			\
      if (write_symbols != SDB_DEBUG)					\
	i386_pe_declare_function_type (FILE, NAME, TREE_PUBLIC (DECL));	\
      ASM_OUTPUT_LABEL (FILE, NAME);					\
    }									\
  while (0)

/* Add an external function to the list of functions to be declared at
   the end of the file.  */
#define ASM_OUTPUT_EXTERNAL(FILE, DECL, NAME)				\
  do									\
    {									\
      if (TREE_CODE (DECL) == FUNCTION_DECL)				\
	i386_pe_record_external_function (NAME);			\
    }									\
  while (0)

/* Declare the type properly for any external libcall.  */
#define ASM_OUTPUT_EXTERNAL_LIBCALL(FILE, FUN) \
  i386_pe_declare_function_type (FILE, XSTR (FUN, 0), 1)

/* This says out to put a global symbol in the BSS section.  */
#undef ASM_OUTPUT_ALIGNED_BSS
#define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN) \
  asm_output_aligned_bss ((FILE), (DECL), (NAME), (SIZE), (ALIGN))

/* Output function declarations at the end of the file.  */
#undef ASM_FILE_END
#define ASM_FILE_END(FILE) \
  i386_pe_asm_file_end (FILE)

#undef ASM_COMMENT_START
#define ASM_COMMENT_START " #"

/* DWARF2 Unwinding doesn't work with exception handling yet.  To make
   it work, we need to build a libgcc_s.dll, and dcrt0.o should be
   changed to call __register_frame_info/__deregister_frame_info.  */
#define DWARF2_UNWIND_INFO 0

/* Don't assume anything about the header files.  */
#define NO_IMPLICIT_EXTERN_C

#undef PROFILE_HOOK
#define PROFILE_HOOK(LABEL)						\
  if (MAIN_NAME_P (DECL_NAME (current_function_decl)))			\
    {									\
      emit_call_insn (gen_rtx (CALL, VOIDmode,				\
	gen_rtx_MEM (FUNCTION_MODE,					\
		     gen_rtx_SYMBOL_REF (Pmode, "_monstartup")),	\
	const0_rtx));							\
    }

/* Java Native Interface (JNI) methods on Win32 are invoked using the
   stdcall calling convention.  */
#undef MODIFY_JNI_METHOD_CALL
#define MODIFY_JNI_METHOD_CALL(MDECL)					      \
  build_type_attribute_variant ((MDECL),				      \
			       build_tree_list (get_identifier ("stdcall"),   \
						NULL))


/* External function declarations.  */

extern void i386_pe_record_external_function PARAMS ((const char *));
extern void i386_pe_declare_function_type PARAMS ((FILE *, const char *, int));
extern void i386_pe_record_exported_symbol PARAMS ((const char *, int));
extern void i386_pe_asm_file_end PARAMS ((FILE *));
extern int i386_pe_dllexport_name_p PARAMS ((const char *));
extern int i386_pe_dllimport_name_p PARAMS ((const char *));

/* For Win32 ABI compatibility */
#undef DEFAULT_PCC_STRUCT_RETURN
#define DEFAULT_PCC_STRUCT_RETURN 0

/* No data type wants to be aligned rounder than this.  */
#undef	BIGGEST_ALIGNMENT
#define BIGGEST_ALIGNMENT 128

/* Native complier aligns internal doubles in structures on dword boundaries.  */
#undef	BIGGEST_FIELD_ALIGNMENT
#define BIGGEST_FIELD_ALIGNMENT 64

/* A bit-field declared as `int' forces `int' alignment for the struct.  */
#undef PCC_BITFIELD_TYPE_MATTERS
#define PCC_BITFIELD_TYPE_MATTERS 1
#define GROUP_BITFIELDS_BY_ALIGN TYPE_NATIVE(rec)


/* Enable alias attribute support.  */
#ifndef SET_ASM_OP
#define SET_ASM_OP "\t.set\t"
#endif

/* Override GCC's relative pathname lookup (ie., relocatability) unless
   otherwise told by other subtargets.  */
#ifndef WIN32_NO_ABSOLUTE_INST_DIRS
#undef MD_STARTFILE_PREFIX
#define MD_STARTFILE_PREFIX     "/usr/lib/"

#undef STANDARD_STARTFILE_PREFIX
#define STANDARD_STARTFILE_PREFIX     "/usr/lib/mingw/"

#ifndef CROSS_COMPILE
#undef LOCAL_INCLUDE_DIR
#undef TOOL_INCLUDE_DIR
#undef SYSTEM_INCLUDE_DIR
#undef STANDARD_INCLUDE_DIR
#define STANDARD_INCLUDE_DIR 0
#endif /* not CROSS_COMPILE */
#endif /* not WIN32_NO_ABSOLUTE_INST_DIRS */

#undef TREE

#ifndef BUFSIZ
# undef FILE
#endif