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=554d5e1f47970f9197a92dd92e13ea8485c26892'>root</a>/<a href='/guix/log/build-aux?id=554d5e1f47970f9197a92dd92e13ea8485c26892'>build-aux</a>/<a href='/guix/log/build-aux/update-NEWS.scm?id=554d5e1f47970f9197a92dd92e13ea8485c26892'>update-NEWS.scm</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/build-aux/update-NEWS.scm?id=554d5e1f47970f9197a92dd92e13ea8485c26892&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-05-10 13:48:02 -0400'>2021-05-10</span></td><td><a href='/guix/commit/build-aux/update-NEWS.scm?id=ed2d4d52dde00bdccc1bb2c93b24ffcc72a7fcd3'>maint: update-NEWS: Sort packages prior writing to the data file.</a><span class='msg-avail'>...<span class='msg-tooltip'>* build-aux/update-NEWS.scm (main): Sort packages.
</span></span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2021-04-23 21:32:46 -0400'>2021-04-23</span></td><td><a href='/guix/commit/build-aux/update-NEWS.scm?id=18dc8c6f0f76b8d128638105eebad2895f9857f0'>build-aux: Relax the regexp used to match NEWS sections.</a><span class='msg-avail'>...<span class='msg-tooltip'>A number of packages doesn't really make sense in the name of the section to
be substituted.  This change allows using simply '*** new packages' instead of
'*** 1999 new packages', for example, and have the update-NEWS.scm script
update it.

* build-aux/update-NEWS.scm (write-packages-added) &lt;regexp&gt;: Do not care about
leading white space in the name of the section.
</span></span></td><td>Maxim Cournoyer</td></tr>