libvips/m4/zlib.m4

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dnl From FIND_MOTIF and ACX_PTHREAD, without much understanding
dnl
dnl FIND_ZLIB[ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]]
dnl ------------------------------------------------
dnl
dnl Find zlib libraries and headers ... useful for platforms which are missing
dnl the zlib .pc file
dnl
dnl Put compile stuff in ZLIB_INCLUDES
dnl Put link stuff in ZLIB_LIBS
dnl Define HAVE_ZLIB if found
dnl
AC_DEFUN([FIND_ZLIB], [
AC_REQUIRE([AC_PATH_XTRA])
ZLIB_INCLUDES=""
ZLIB_LIBS=""
AC_ARG_WITH(zlib,
AS_HELP_STRING([--without-zlib], [build without zlib (default: test)]))
# Treat --without-zlib like --without-zlib-includes --without-zlib-libraries.
if test "$with_zlib" = "no"; then
ZLIB_INCLUDES=no
ZLIB_LIBS=no
fi
AC_ARG_WITH(zlib-includes,
AS_HELP_STRING([--with-zlib-includes=DIR], [libz includes are in DIR]),
ZLIB_INCLUDES="-I$withval")
AC_ARG_WITH(zlib-libraries,
AS_HELP_STRING([--with-zlib-libraries=DIR], [libz libraries are in DIR]),
ZLIB_LIBS="-L$withval -lz")
AC_MSG_CHECKING(for ZLIB)
# Look for zlib.h
if test "$ZLIB_INCLUDES" = ""; then
# Check the standard search path
AC_TRY_COMPILE([#include <stdio.h>
#include <zlib.h>],[int a;],[
ZLIB_INCLUDES=""
], [
# zlib.h is not in the standard search path, try
# $prefix
zlib_save_CFLAGS="$CFLAGS"
CFLAGS="-I${prefix}/include $CFLAGS"
AC_TRY_COMPILE([#include <stdio.h>
#include <zlib.h>],[int a;],[
ZLIB_INCLUDES="-I${prefix}/include"
], [
ZLIB_INCLUDES="no"
])
CFLAGS=$zlib_save_CFLAGS
])
fi
# Now for the libraries
if test "$ZLIB_LIBS" = ""; then
zlib_save_LIBS="$LIBS"
zlib_save_CFLAGS="$CFLAGS"
LIBS="-lz $LIBS"
CFLAGS="$ZLIB_INCLUDES $CFLAGS"
# Try the standard search path first
AC_TRY_LINK([#include <stdio.h>
#include <zlib.h>
],[z_stream zs;inflateInit2(&zs, 15 | 32)], [
ZLIB_LIBS="-lz"
], [
# libz is not in the standard search path, try $prefix
LIBS="-L${prefix}/lib $LIBS"
AC_TRY_LINK([#include <stdio.h>
#include <zlib.h>
],[z_stream zs;inflateInit2(&zs, 15 | 32)], [
ZLIB_LIBS="-L${prefix}/lib -lz"
], [
ZLIB_LIBS=no
])
])
LIBS="$zlib_save_LIBS"
CFLAGS="$zlib_save_CFLAGS"
fi
AC_SUBST(ZLIB_LIBS)
AC_SUBST(ZLIB_INCLUDES)
# Print a helpful message
zlib_libraries_result="$ZLIB_LIBS"
zlib_includes_result="$ZLIB_INCLUDES"
if test x"$zlib_libraries_result" = x""; then
zlib_libraries_result="in default path"
fi
if test x"$zlib_includes_result" = x""; then
zlib_includes_result="in default path"
fi
if test "$zlib_libraries_result" = "no"; then
zlib_libraries_result="(none)"
fi
if test "$zlib_includes_result" = "no"; then
zlib_includes_result="(none)"
fi
AC_MSG_RESULT([libraries $zlib_libraries_result, headers $zlib_includes_result])
# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
if test "$ZLIB_INCLUDES" != "no" && test "$ZLIB_LIBS" != "no"; then
AC_DEFINE(HAVE_ZLIB,1,[Define if you have zlib libraries and header files.])
$1
else
ZLIB_INCLUDES=""
ZLIB_LIBS=""
$2
fi
])dnl