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})
lue='switch'/></form></td></tr>
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<div class='path'>path: <a href='/guix/log/?id=3cdf7d8fbcb39273230ed0e253395965b6f7f375'>root</a>/<a href='/guix/log/.gitignore?id=3cdf7d8fbcb39273230ed0e253395965b6f7f375'>.gitignore</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/.gitignore?id=3cdf7d8fbcb39273230ed0e253395965b6f7f375&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-04-24 15:32:54 +0100'>2023-04-24</span></td><td><a href='/guix/commit/.gitignore?id=23f11afacdfe755ffa514a8cbf93ba1121b9db0d'>Add mumi config.</a><span class='msg-avail'>...<span class='msg-tooltip'>* .mumi/config: New file.
* .gitignore: Add .mumi/current-issue.
</span></span></td><td>Arun Isaac</td></tr>
<tr><td><span title='2022-07-03 14:12:32 +0200'>2022-07-03</span></td><td><a href='/guix/commit/.gitignore?id=4eaf90470f466b3fdab87f6961cb18bb348d433f'>etc: Add teams.scm.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/teams.scm.in: New file.
* configure.ac: Generate executable.
* .gitignore: Ignore generated file.
</span></span></td><td>Ricardo Wurmus</td></tr>
<tr><td><span title='2022-06-05 21:27:53 +0200'>2022-06-05</span></td><td><a href='/guix/commit/.gitignore?id=4d47c2c723927ad4ad4142bd517c6ccc03c27528'>gitignore: Add .DS_Store.</a><span class='msg-avail'>...<span class='msg-tooltip'>Ignore MacOS specific file: https://en.wikipedia.org/wiki/.DS_Store

Signed-off-by: Mathieu Othacehe &lt;othacehe@gnu.org&gt;
</span></span></td><td>Pavel Shlyak</td></tr>