Controlling the Compilation Driver, `gcc'
=========================================

   You can control the compilation driver.

`SWITCH_TAKES_ARG (CHAR)'
     A C expression which determines whether the option `-CHAR' takes
     arguments.  The value should be the number of arguments that
     option takes-zero, for many options.

     By default, this macro is defined to handle the standard options
     properly.  You need not define it unless you wish to add additional
     options which take arguments.

`WORD_SWITCH_TAKES_ARG (NAME)'
     A C expression which determines whether the option `-NAME' takes
     arguments.  The value should be the number of arguments that
     option takes-zero, for many options.  This macro rather than
     `SWITCH_TAKES_ARG' is used for multi-character option names.

     By default, this macro is defined as
     `DEFAULT_WORD_SWITCH_TAKES_ARG', which handles the standard options
     properly.  You need not define `WORD_SWITCH_TAKES_ARG' unless you
     wish to add additional options which take arguments.  Any
     redefinition should call `DEFAULT_WORD_SWITCH_TAKES_ARG' and then
     check for additional options.

`SWITCHES_NEED_SPACES'
     A string-valued C expression which is nonempty if the linker needs
     a space between the `-L' or `-o' option and its argument.

     If this macro is not defined, the default value is 0.

`CPP_SPEC'
     A C string constant that tells the GNU CC driver program options to
     pass to CPP.  It can also specify how to translate options you
     give to GNU CC into options for GNU CC to pass to the CPP.

     Do not define this macro if it does not need to do anything.

`NO_BUILTIN_SIZE_TYPE'
     If this macro is defined, the preprocessor will not define the
     builtin macro `__SIZE_TYPE__'.  The macro `__SIZE_TYPE__' must
     then be defined by `CPP_SPEC' instead.

     This should be defined if `SIZE_TYPE' depends on target dependent
     flags which are not accessible to the preprocessor.  Otherwise, it
     should not be defined.

`NO_BUILTIN_PTRDIFF_TYPE'
     If this macro is defined, the preprocessor will not define the
     builtin macro `__PTRDIFF_TYPE__'.  The macro `__PTRDIFF_TYPE__'
     must then be defined by `CPP_SPEC' instead.

     This should be defined if `PTRDIFF_TYPE' depends on target
     dependent flags which are not accessible to the preprocessor.
     Otherwise, it should not be defined.

`SIGNED_CHAR_SPEC'
     A C string constant that tells the GNU CC driver program options to
     pass to CPP.  By default, this macro is defined to pass the option
     `-D__CHAR_UNSIGNED__' to CPP if `char' will be treated as
     `unsigned char' by `cc1'.

     Do not define this macro unless you need to override the default
     definition.

`CC1_SPEC'
     A C string constant that tells the GNU CC driver program options to
     pass to `cc1'.  It can also specify how to translate options you
     give to GNU CC into options for GNU CC to pass to the `cc1'.

     Do not define this macro if it does not need to do anything.

`CC1PLUS_SPEC'
     A C string constant that tells the GNU CC driver program options to
     pass to `cc1plus'.  It can also specify how to translate options
     you give to GNU CC into options for GNU CC to pass to the
     `cc1plus'.

     Do not define this macro if it does not need to do anything.

`ASM_SPEC'
     A C string constant that tells the GNU CC driver program options to
     pass to the assembler.  It can also specify how to translate
     options you give to GNU CC into options for GNU CC to pass to the
     assembler.  See the file `sun3.h' for an example of this.

     Do not define this macro if it does not need to do anything.

`ASM_FINAL_SPEC'
     A C string constant that tells the GNU CC driver program how to
     run any programs which cleanup after the normal assembler.
     Normally, this is not needed.  See the file `mips.h' for an
     example of this.

     Do not define this macro if it does not need to do anything.

`LINK_SPEC'
     A C string constant that tells the GNU CC driver program options to
     pass to the linker.  It can also specify how to translate options
     you give to GNU CC into options for GNU CC to pass to the linker.

     Do not define this macro if it does not need to do anything.

`LIB_SPEC'
     Another C string constant used much like `LINK_SPEC'.  The
     difference between the two is that `LIB_SPEC' is used at the end
     of the command given to the linker.

     If this macro is not defined, a default is provided that loads the
     standard C library from the usual place.  See `gcc.c'.

`LIBGCC_SPEC'
     Another C string constant that tells the GNU CC driver program how
     and when to place a reference to `libgcc.a' into the linker
     command line.  This constant is placed both before and after the
     value of `LIB_SPEC'.

     If this macro is not defined, the GNU CC driver provides a default
     that passes the string `-lgcc' to the linker unless the `-shared'
     option is specified.

`STARTFILE_SPEC'
     Another C string constant used much like `LINK_SPEC'.  The
     difference between the two is that `STARTFILE_SPEC' is used at the
     very beginning of the command given to the linker.

     If this macro is not defined, a default is provided that loads the
     standard C startup file from the usual place.  See `gcc.c'.

`ENDFILE_SPEC'
     Another C string constant used much like `LINK_SPEC'.  The
     difference between the two is that `ENDFILE_SPEC' is used at the
     very end of the command given to the linker.

     Do not define this macro if it does not need to do anything.

`LINK_LIBGCC_SPECIAL'
     Define this macro if the driver program should find the library
     `libgcc.a' itself and should not pass `-L' options to the linker.
     If you do not define this macro, the driver program will pass the
     argument `-lgcc' to tell the linker to do the search and will pass
     `-L' options to it.

`LINK_LIBGCC_SPECIAL_1'
     Define this macro if the driver program should find the library
     `libgcc.a'.  If you do not define this macro, the driver program
     will pass the argument `-lgcc' to tell the linker to do the search.
     This macro is similar to `LINK_LIBGCC_SPECIAL', except that it does
     not affect `-L' options.

`MULTILIB_DEFAULTS'
     Define this macro as a C expression for the initializer of an
     array of string to tell the driver program which options are
     defaults for this target and thus do not need to be handled
     specially when using `MULTILIB_OPTIONS'.

     Do not define this macro if `MULTILIB_OPTIONS' is not defined in
     the target makefile fragment or if none of the options listed in
     `MULTILIB_OPTIONS' are set by default.  See Target Fragment.

`RELATIVE_PREFIX_NOT_LINKDIR'
     Define this macro to tell `gcc' that it should only translate a
     `-B' prefix into a `-L' linker option if the prefix indicates an
     absolute file name.

`STANDARD_EXEC_PREFIX'
     Define this macro as a C string constant if you wish to override
     the standard choice of `/usr/local/lib/gcc-lib/' as the default
     prefix to try when searching for the executable files of the
     compiler.

`MD_EXEC_PREFIX'
     If defined, this macro is an additional prefix to try after
     `STANDARD_EXEC_PREFIX'.  `MD_EXEC_PREFIX' is not searched when the
     `-b' option is used, or the compiler is built as a cross compiler.

`STANDARD_STARTFILE_PREFIX'
     Define this macro as a C string constant if you wish to override
     the standard choice of `/usr/local/lib/' as the default prefix to
     try when searching for startup files such as `crt0.o'.

`MD_STARTFILE_PREFIX'
     If defined, this macro supplies an additional prefix to try after
     the standard prefixes.  `MD_EXEC_PREFIX' is not searched when the
     `-b' option is used, or when the compiler is built as a cross
     compiler.

`MD_STARTFILE_PREFIX_1'
     If defined, this macro supplies yet another prefix to try after the
     standard prefixes.  It is not searched when the `-b' option is
     used, or when the compiler is built as a cross compiler.

`INIT_ENVIRONMENT'
     Define this macro as a C string constant if you with to set
     environment variables for programs called by the driver, such as
     the assembler and loader.  The driver passes the value of this
     macro to `putenv' to initialize the necessary environment
     variables.

`LOCAL_INCLUDE_DIR'
     Define this macro as a C string constant if you wish to override
     the standard choice of `/usr/local/include' as the default prefix
     to try when searching for local header files.  `LOCAL_INCLUDE_DIR'
     comes before `SYSTEM_INCLUDE_DIR' in the search order.

     Cross compilers do not use this macro and do not search either
     `/usr/local/include' or its replacement.

`SYSTEM_INCLUDE_DIR'
     Define this macro as a C string constant if you wish to specify a
     system-specific directory to search for header files before the
     standard directory.  `SYSTEM_INCLUDE_DIR' comes before
     `STANDARD_INCLUDE_DIR' in the search order.

     Cross compilers do not use this macro and do not search the
     directory specified.

`STANDARD_INCLUDE_DIR'
     Define this macro as a C string constant if you wish to override
     the standard choice of `/usr/include' as the default prefix to try
     when searching for header files.

     Cross compilers do not use this macro and do not search either
     `/usr/include' or its replacement.

`INCLUDE_DEFAULTS'
     Define this macro if you wish to override the entire default
     search path for include files.  The default search path includes
     `GCC_INCLUDE_DIR', `LOCAL_INCLUDE_DIR', `SYSTEM_INCLUDE_DIR',
     `GPLUSPLUS_INCLUDE_DIR', and `STANDARD_INCLUDE_DIR'.  In addition,
     `GPLUSPLUS_INCLUDE_DIR' and `GCC_INCLUDE_DIR' are defined
     automatically by `Makefile', and specify private search areas for
     GCC.  The directory `GPLUSPLUS_INCLUDE_DIR' is used only for C++
     programs.

     The definition should be an initializer for an array of structures.
     Each array element should have two elements: the directory name (a
     string constant) and a flag for C++-only directories.  Mark the
     end of the array with a null element.  For example, here is the
     definition used for VMS:

          #define INCLUDE_DEFAULTS \
          {                                       \
            { "GNU_GXX_INCLUDE:", 1},             \
            { "GNU_CC_INCLUDE:", 0},              \
            { "SYS$SYSROOT:[SYSLIB.]", 0},        \
            { ".", 0},                            \
            { 0, 0}                               \
          }

   Here is the order of prefixes tried for exec files:

  1. Any prefixes specified by the user with `-B'.

  2. The environment variable `GCC_EXEC_PREFIX', if any.

  3. The directories specified by the environment variable
     `COMPILER_PATH'.

  4. The macro `STANDARD_EXEC_PREFIX'.

  5. `/usr/lib/gcc/'.

  6. The macro `MD_EXEC_PREFIX', if any.

   Here is the order of prefixes tried for startfiles:

  1. Any prefixes specified by the user with `-B'.

  2. The environment variable `GCC_EXEC_PREFIX', if any.

  3. The directories specified by the environment variable
     `LIBRARY_PATH' (native only, cross compilers do not use this).

  4. The macro `STANDARD_EXEC_PREFIX'.

  5. `/usr/lib/gcc/'.

  6. The macro `MD_EXEC_PREFIX', if any.

  7. The macro `MD_STARTFILE_PREFIX', if any.

  8. The macro `STANDARD_STARTFILE_PREFIX'.

  9. `/lib/'.

 10. `/usr/lib/'.