These macros check for particular programs--whether they exist, and in some cases whether they support certain features.
YYTEXT_POINTER if yytext is a `char *' instead
of a `char []'. Also set output variable LEX_OUTPUT_ROOT to
the base of the file name that the lexer generates; usually
`lex.yy', but sometimes something else. These results vary
according to whether lex or flex is being used.
mawk, gawk, nawk, and awk, in that
order, and set output variable AWK to the first one that it
finds. It tries mawk first because that is reported to be the
fastest implementation.
CC is not already set in the
environment, check for gcc, and use cc if it's not found.
Set output variable CC to the name of the compiler found.
If using the GNU C compiler, set shell variable GCC to
`yes', empty otherwise. If output variable CFLAGS was
not already set, set it to `-g -O' for the GNU C compiler
(`-O' on systems where GCC does not accept `-g'), or `-g'
for other compilers.
NO_MINUS_C_MINUS_O.
CPP to a command that runs the
C preprocessor. If `$CC -E' doesn't work, it uses `/lib/cpp'.
It is only portable to run CPP on files with a `.c'
extension.
If the current language is C (see section Language Choice), many of the
specific test macros use the value of CPP indirectly by calling
AC_TRY_CPP, AC_CHECK_HEADER, AC_EGREP_HEADER, or
AC_EGREP_CPP.
CXX or CCC (in that order) is set; if so, set output
variable CXX to its value. Otherwise search for a C++ compiler
under likely names (c++, g++, gcc, CC, and
cxx). If none of those checks succeed, as a last resort set
CXX to gcc.
If using the GNU C++ compiler, set shell variable GXX to
`yes', empty otherwise. If output variable CXXFLAGS was
not already set, set it to `-g -O' for the GNU C++ compiler
(`-O' on systems where G++ does not accept `-g'), or `-g'
for other compilers.
CXXCPP to a command that runs the
C++ preprocessor. If `$CXX -E' doesn't work, it uses `/lib/cpp'.
It is only portable to run CXXCPP on files with a `.c',
`.C', or `.cc' extension.
If the current language is C++ (see section Language Choice), many of the
specific test macros use the value of CXXCPP indirectly by
calling AC_TRY_CPP, AC_CHECK_HEADER,
AC_EGREP_HEADER, or AC_EGREP_CPP.
CC if using the
GNU C compiler and ioctl does not work properly without
`-traditional'. That usually happens when the fixed header files
have not been installed on an old system. Since recent versions of the
GNU C compiler fix the header files automatically when installed, this
is becoming a less prevalent problem.
INSTALL to the path of a BSD compatible
install program, if one is found in the current PATH.
Otherwise, set INSTALL to `dir/install-sh -c',
checking the directories specified to AC_CONFIG_AUX_DIR (or its
default directories) to determine dir (see section Creating Output Files). Also set
the variable INSTALL_PROGRAM to `${INSTALL}' and
INSTALL_DATA to `${INSTALL} -m 644'.
This macro screens out various instances of install known to not
work. It prefers to find a C program rather than a shell script, for
speed. Instead of `install-sh', it can also use `install.sh',
but that name is obsolete because some make programs have a rule
that creates `install' from it if there is no `Makefile'.
A copy of `install-sh' which you may use comes with Autoconf. If
you use AC_PROG_INSTALL, you must include either
`install-sh' or `install.sh' in your distribution, or
configure will produce an error message saying it can't find
them--even if the system you're on has a good install program.
This check is a safety measure to prevent you from accidentally leaving
that file out, which would prevent your package from installing on
systems that don't have a BSD-compatible install program.
If you need to use your own installation program because it has
features not found in standard install programs, there is no
reason to use AC_PROG_INSTALL; just put the pathname of your
program into your `Makefile.in' files.
flex is found, set output variable LEX to
`flex' and LEXLIB to `-lfl', if that library is in a
standard place. Otherwise set LEX to `lex' and
LEXLIB to `-ll'.
LN_S to `ln -s', otherwise set it to `ln'.
RANLIB to `ranlib' if ranlib
is found, otherwise to `:' (do nothing).
bison is found, set output variable YACC to
`bison -y'. Otherwise, if byacc is found, set YACC
to `byacc'. Otherwise set YACC to `yacc'.