Merge branch 'bjorn/erts/zlib-1.2.8'

* bjorn/erts/zlib-1.2.8:
  configure: Prefer the system's zlib over own our zlib source
  Update preloaded modules
  Add the 'rle' zstrategy
  Don't make gzio.c dependent on the zutil.h header file
  Update zlib to 1.2.8
  erts/zlib: Remove unused file example.c

1 files changed, 33 insertions, 13 deletions

diff --git a/erts/configure.in b/erts/configure.in
index cf21d0cbfc..c992fb5bd9 100644
--- a/erts/configure.in
+++ b/erts/configure.in
@@ -1372,24 +1372,44 @@ dnl -------------
 dnl zlib
 dnl -------------
 
-AC_ARG_ENABLE(shared-zlib,
-AS_HELP_STRING([--enable-shared-zlib], [enable using shared zlib library]),
-[ case "$enableval" in
-    no) enable_shared_zlib=no ;;
-    *)  enable_shared_zlib=yes ;;
-  esac ], enable_shared_zlib=no)
+AC_ARG_ENABLE(builtin-zlib,
+  AS_HELP_STRING([--enable-builtin-zlib],
+                 [force use of our own built-in zlib]),
+  [ case "$enableval" in
+      no) enable_builtin_zlib=no ;;
+      *)  enable_builtin_zlib=yes ;;
+    esac ], enable_builtin_zlib=no)
 
 Z_LIB=
 
-if test "x$enable_shared_zlib" = "xyes" ; then
-	AC_CHECK_LIB(z, adler32_combine,
-		[Z_LIB="-lz"
-		 AC_DEFINE(HAVE_LIBZ, 1, [Define to 1 if you have the `z' library (-lz).])],
-		[AC_MSG_ERROR([cannot find any shared zlib])])
+if test "x$enable_builtin_zlib" = "xyes"; then
+  AC_MSG_NOTICE([Using our own built-in zlib source])
 else
-	AC_MSG_NOTICE([Using own zlib source])
+AC_MSG_CHECKING(for zlib 1.2.5 or higher)
+zlib_save_LIBS=$LIBS
+LIBS="-lz $LIBS"
+AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM([[
+#include "zlib.h"
+]],[[
+#if ZLIB_VERNUM >= 0x1250
+  Bytef s[1];
+  s[0] = 0;
+  (void) adler32((uLong)0, s, 1);
+#else
+#error "No zlib 1.2.5 or higher found"
+error
+#endif
+]])],
+[
+ Z_LIB="-lz"
+ AC_DEFINE(HAVE_LIBZ, 1, [Define to 1 if you have the `z' library (-lz).])
+ AC_MSG_RESULT(yes)
+],[
+ AC_MSG_RESULT(no)
+])
+LIBS=$zlib_save_LIBS
 fi
-
 AC_SUBST(Z_LIB)
 
 dnl