build: bump b64 to ce864b17ea0e24a91e77c7dd3eb2d1ac4175b3f0.

This version includes a fix so that it does not include the headers
for size_t twice.

Signed-off-by: Lorenzo Fontana <fontanalorenz@gmail.com>

CMakeLists.txt

@@ -123,8 +123,8 @@ set(B64_INCLUDE "${B64_SRC}/include")
 set(B64_LIB "${B64_SRC}/src/libb64.a")
 ExternalProject_Add(
   b64
-  URL "https://github.com/libb64/libb64/archive/v2.0.0.1.tar.gz"
-  URL_HASH "SHA256=ce8e578a953a591bd4a6f157eec310b9a4c2e6f10ade2fdda6ae6bafaf798b98"
+  URL "https://github.com/libb64/libb64/archive/ce864b17ea0e24a91e77c7dd3eb2d1ac4175b3f0.tar.gz"
+  URL_HASH "SHA256=d07173e66f435e5c77dbf81bd9313f8d0e4a3b4edd4105a62f4f8132ba932811"
   CONFIGURE_COMMAND ""
   BUILD_COMMAND ${CMD_MAKE}
   BUILD_IN_SOURCE 1