build: Allow to use external liblz4 instead of embedded copy

While we are likely will keep the embedded copy for a while to avoid a really
new dependency we allow now to use the external liblz4. You need at least
revision r120 and a package that ships the pc file for it.

Personally I would like to get rid of it rather sooner than later due to the
security implications and a bunch of code we ship but have no idea about.
Reality is that it will need some time until this new lib is actually
packaged and shipped with releases for a a majority of people.

This patch was co-worked with Doug Newgard <scimmia22@outlook.com>

1 files changed, 22 insertions, 0 deletions

diff --git a/configure.ac b/configure.ac
index 801ac1e15c..3247ee6866 100644
--- a/configure.ac
+++ b/configure.ac
@@ -374,6 +374,28 @@ AC_DEFINE_IF([ENABLE_LUA_OLD], [test "${want_lua_old}" = "yes"],
   [1], [Use interpreted Lua (5.1 or 5.2)])
 AC_SUBST([want_lua_old])
 
+
+want_liblz4="no"
+AC_ARG_ENABLE([liblz4],
+   [AS_HELP_STRING([--enable-liblz4],[Enable usage of liblz4 instead of our embedded copy. @<:@default=disabled@:>@])],
+   [
+    if test "x${enableval}" = "xyes" ; then
+        # Only ships pc file since r120
+        PKG_CHECK_MODULES([LIBLZ4], [liblz4])
+        EFL_DEPEND_PKG([EET], [LIBLZ4], [liblz4])
+        EFL_DEPEND_PKG([EVAS], [LIBLZ4], [liblz4])
+       want_liblz4="yes"
+    else
+       want_liblz4="no"
+    fi
+   ],
+   [want_liblz4="no"])
+
+AM_CONDITIONAL([ENABLE_LIBLZ4], [test "${want_liblz4}" = "yes"])
+AC_DEFINE_IF([ENABLE_LIBLZ4], [test "${want_liblz4}" = "yes"], [1], [Use liblz4 external library instead of embedded copy])
+AC_SUBST([want_liblz4])
+AC_SUBST([ENABLE_LIBLZ4])
+
 #### Checks for header files
 
 # Common Checks (keep names sorted for ease of use):