Fix build failure when using Swig 4.

Taken from upstream:
https://github.com/fifengine/fifengine/commit/d14f232f4cd9a00b05d6872957070e8c020f515d

diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -893,7 +893,7 @@ if(build-python)
   find_package(PythonLibs ${PYTHON_VERSION_STRING} EXACT)
   include_directories(${PYTHON_INCLUDE_PATH})
 
-  set(CMAKE_SWIG_FLAGS -modern -fastdispatch -dirvtable -nosafecstrings -noproxydel -fastproxy -fastinit -fastunpack -fastquery -modernargs -nobuildnone -keyword -w511 -w473 -w404 -w314)
+  set(CMAKE_SWIG_FLAGS -modern -fastdispatch -dirvtable -noproxydel -fastproxy -fastinit -fastunpack -fastquery -modernargs -keyword -w511 -w473 -w404 -w314)
 
   set_source_files_properties("${PROJECT_BINARY_DIR}/fife.i" PROPERTIES CPLUSPLUS ON)
   set(FIFE_SOURCES ${FIFE_CORE_SRC})
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<tr><td><span title='2021-12-13 17:48:25 +0100'>2021-12-13</span></td><td><a href='/guix/commit/gnu/packages/serveez.scm?id=8394619baceb118df92e355377fd543bb1aa501a'>gnu: Simplify package inputs.</a><span class='msg-avail'>...<span class='msg-tooltip'>This commit was obtained by running:

  ./pre-inst-env guix style

without any additional argument.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-12-12 10:59:07 +0200'>2021-12-12</span></td><td><a href='/guix/commit/gnu/packages/serveez.scm?id=70fba40048a09412e5c05a2a169a30b324942460'>gnu: serveez: Update to 0.3.0.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/serveez.scm (serveez): Update to 0.3.0.
[source]: Download using lzip tarball.
[native-inputs]: Add lzip.
[inputs]: Replace guile-2.0 with guile-2.2.
</span></span></td><td>Efraim Flashner</td></tr>