Bug 1375859 - Build zlib in libmozglue when the linker in enabled. r=mshal

The linker uses zlib. The linker is in mozglue, zlib is in libxul by
default. As a consequence, we made --with-system-zlib a requirement for
builds enabling the linker.

In the meanwhile, we added an option that makes zlib built in mozglue
for different needs, which, in fact, also allows to do that when the
linker is enabled.

So, allow to build without system zlib when the linker is enabled.

--HG--
extra : rebase_source : 873a87b17b306fc392018049e01cf794b63a6206

mozglue/linker/tests/moz.build

@@ -14,7 +14,10 @@ USE_LIBS += [
     'linker',
     'mfbt',
 ]
-OS_LIBS += CONFIG['MOZ_ZLIB_LIBS']
+if CONFIG['ZLIB_IN_MOZGLUE']:
+    USE_LIBS += [ 'modules_zlib_src' ]
+else:
+    OS_LIBS += CONFIG['MOZ_ZLIB_LIBS']
 DISABLE_STL_WRAPPING = True
 
 PYTHON_UNITTEST_MANIFESTS += ['python.ini']

old-configure.in

@@ -2035,10 +2035,6 @@ dnl system ZLIB support
 dnl ========================================================
 MOZ_ZLIB_CHECK([1.2.3])
 
-if test "$MOZ_LINKER" = 1 -a "$MOZ_SYSTEM_ZLIB" != 1; then
-    AC_MSG_ERROR([Custom dynamic linker requires --with-system-zlib])
-fi
-
 if test -z "$SKIP_LIBRARY_CHECKS"; then
 dnl system BZIP2 Support
 dnl ========================================================
@@ -4557,7 +4553,7 @@ dnl ========================================================
 MOZ_ARG_HEADER(Static build options)
 
 if test -z "$MOZ_SYSTEM_ZLIB"; then
-if test -n "$JS_SHARED_LIBRARY"; then
+if test -n "$JS_SHARED_LIBRARY" -o -n "$MOZ_LINKER"; then
   ZLIB_IN_MOZGLUE=1
   AC_DEFINE(ZLIB_IN_MOZGLUE)
 fi