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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<div class='path'>path: <a href='/guix/log/?id=86fb0e039bf30cf85e2066401f9a384427c47ea8'>root</a>/<a href='/guix/log/CODE-OF-CONDUCT?id=86fb0e039bf30cf85e2066401f9a384427c47ea8'>CODE-OF-CONDUCT</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/CODE-OF-CONDUCT?id=86fb0e039bf30cf85e2066401f9a384427c47ea8&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2022-03-01 13:18:01 -0500'>2022-03-01</span></td><td><a href='/guix/commit/CODE-OF-CONDUCT?id=c67912011154e2b347cdf6f3e633e87fd44f409c'>CODE-OF-CONDUCT: Add a top notice.</a><span class='msg-avail'>...</span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2022-03-01 13:07:04 -0500'>2022-03-01</span></td><td><a href='/guix/commit/CODE-OF-CONDUCT?id=4254d74b4ca6d4aa78b7fa055fc9ec72a2e93ad3'>CODE-OF-CONDUCT: Update to version 2.1.</a><span class='msg-avail'>...</span></td><td>Maxim Cournoyer</td></tr>