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Annotation of embedaddon/libiconv/srcm4/absolute-header.m4, revision 1.1.1.1

1.1       misho       1: # absolute-header.m4 serial 16
                      2: dnl Copyright (C) 2006-2019 Free Software Foundation, Inc.
                      3: dnl This file is free software; the Free Software Foundation
                      4: dnl gives unlimited permission to copy and/or distribute it,
                      5: dnl with or without modifications, as long as this notice is preserved.
                      6: 
                      7: dnl From Derek Price.
                      8: 
                      9: # gl_ABSOLUTE_HEADER(HEADER1 HEADER2 ...)
                     10: # ---------------------------------------
                     11: # Find the absolute name of a header file, testing first if the header exists.
                     12: # If the header were sys/inttypes.h, this macro would define
                     13: # ABSOLUTE_SYS_INTTYPES_H to the '""' quoted absolute name of sys/inttypes.h
                     14: # in config.h
                     15: # (e.g. '#define ABSOLUTE_SYS_INTTYPES_H "///usr/include/sys/inttypes.h"').
                     16: # The three "///" are to pacify Sun C 5.8, which otherwise would say
                     17: # "warning: #include of /usr/include/... may be non-portable".
                     18: # Use '""', not '<>', so that the /// cannot be confused with a C99 comment.
                     19: # Note: This macro assumes that the header file is not empty after
                     20: # preprocessing, i.e. it does not only define preprocessor macros but also
                     21: # provides some type/enum definitions or function/variable declarations.
                     22: AC_DEFUN([gl_ABSOLUTE_HEADER],
                     23: [AC_REQUIRE([AC_CANONICAL_HOST])
                     24: AC_LANG_PREPROC_REQUIRE()dnl
                     25: dnl FIXME: gl_absolute_header and ac_header_exists must be used unquoted
                     26: dnl until we can assume autoconf 2.64 or newer.
                     27: m4_foreach_w([gl_HEADER_NAME], [$1],
                     28:   [AS_VAR_PUSHDEF([gl_absolute_header],
                     29:                   [gl_cv_absolute_]m4_defn([gl_HEADER_NAME]))dnl
                     30:   AC_CACHE_CHECK([absolute name of <]m4_defn([gl_HEADER_NAME])[>],
                     31:     m4_defn([gl_absolute_header]),
                     32:     [AS_VAR_PUSHDEF([ac_header_exists],
                     33:                     [ac_cv_header_]m4_defn([gl_HEADER_NAME]))dnl
                     34:     AC_CHECK_HEADERS_ONCE(m4_defn([gl_HEADER_NAME]))dnl
                     35:     if test AS_VAR_GET(ac_header_exists) = yes; then
                     36:       gl_ABSOLUTE_HEADER_ONE(m4_defn([gl_HEADER_NAME]))
                     37:     fi
                     38:     AS_VAR_POPDEF([ac_header_exists])dnl
                     39:     ])dnl
                     40:   AC_DEFINE_UNQUOTED(AS_TR_CPP([ABSOLUTE_]m4_defn([gl_HEADER_NAME])),
                     41:                      ["AS_VAR_GET(gl_absolute_header)"],
                     42:                      [Define this to an absolute name of <]m4_defn([gl_HEADER_NAME])[>.])
                     43:   AS_VAR_POPDEF([gl_absolute_header])dnl
                     44: ])dnl
                     45: ])# gl_ABSOLUTE_HEADER
                     46: 
                     47: # gl_ABSOLUTE_HEADER_ONE(HEADER)
                     48: # ------------------------------
                     49: # Like gl_ABSOLUTE_HEADER, except that:
                     50: #   - it assumes that the header exists,
                     51: #   - it uses the current CPPFLAGS,
                     52: #   - it does not cache the result,
                     53: #   - it is silent.
                     54: AC_DEFUN([gl_ABSOLUTE_HEADER_ONE],
                     55: [
                     56:   AC_REQUIRE([AC_CANONICAL_HOST])
                     57:   AC_LANG_CONFTEST([AC_LANG_SOURCE([[#include <]]m4_dquote([$1])[[>]])])
                     58:   dnl AIX "xlc -E" and "cc -E" omit #line directives for header files
                     59:   dnl that contain only a #include of other header files and no
                     60:   dnl non-comment tokens of their own. This leads to a failure to
                     61:   dnl detect the absolute name of <dirent.h>, <signal.h>, <poll.h>
                     62:   dnl and others. The workaround is to force preservation of comments
                     63:   dnl through option -C. This ensures all necessary #line directives
                     64:   dnl are present. GCC supports option -C as well.
                     65:   case "$host_os" in
                     66:     aix*) gl_absname_cpp="$ac_cpp -C" ;;
                     67:     *)    gl_absname_cpp="$ac_cpp" ;;
                     68:   esac
                     69: changequote(,)
                     70:   case "$host_os" in
                     71:     mingw*)
                     72:       dnl For the sake of native Windows compilers (excluding gcc),
                     73:       dnl treat backslash as a directory separator, like /.
                     74:       dnl Actually, these compilers use a double-backslash as
                     75:       dnl directory separator, inside the
                     76:       dnl   # line "filename"
                     77:       dnl directives.
                     78:       gl_dirsep_regex='[/\\]'
                     79:       ;;
                     80:     *)
                     81:       gl_dirsep_regex='\/'
                     82:       ;;
                     83:   esac
                     84:   dnl A sed expression that turns a string into a basic regular
                     85:   dnl expression, for use within "/.../".
                     86:   gl_make_literal_regex_sed='s,[]$^\\.*/[],\\&,g'
                     87:   gl_header_literal_regex=`echo '$1' \
                     88:                            | sed -e "$gl_make_literal_regex_sed"`
                     89:   gl_absolute_header_sed="/${gl_dirsep_regex}${gl_header_literal_regex}/"'{
                     90:       s/.*"\(.*'"${gl_dirsep_regex}${gl_header_literal_regex}"'\)".*/\1/
                     91:       s|^/[^/]|//&|
                     92:       p
                     93:       q
                     94:     }'
                     95: changequote([,])
                     96:   dnl eval is necessary to expand gl_absname_cpp.
                     97:   dnl Ultrix and Pyramid sh refuse to redirect output of eval,
                     98:   dnl so use subshell.
                     99:   AS_VAR_SET([gl_cv_absolute_]AS_TR_SH([[$1]]),
                    100: [`(eval "$gl_absname_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD |
                    101:   sed -n "$gl_absolute_header_sed"`])
                    102: ])