[HAVE_ZLIB=no
PSPP_OPTIONAL_PREREQ([zlib])])
+dnl Avoid interference between zlib's crc32() function and gnulib's
+dnl crc32() function, which have different signatures. PSPP calls
+dnl only gnulib's crc32() directly, but it calls zlib's crc32()
+dnl indirectly through other zlib calls. If we don't rename gnulib's
+dnl crc32(), then zlib will call gnulib's version instead of its own,
+dnl causing failures. (This can happen even if zlib isn't detected
+dnl directly, because other libraries that PSPP uses, e.g. libpng,
+dnl sometimes use zlib themselves.)
+AC_DEFINE(
+ [crc32], [gl_crc32],
+ [Avoid making zlib call gnulib's crc32() instead of its own.])
+
dnl Gnumeric support requires libxml2 and zlib.
if test $HAVE_LIBXML2 = yes && test $HAVE_ZLIB = yes; then
GNM_SUPPORT=yes