gnu: fifengine: Fix build with newer Swig and Python.

* gnu/packages/patches/fifengine-swig-compat.patch: New file.
* gnu/local.mk (dist_patch_DATA): Adjust accordingly.
* gnu/packages/games.scm (fifengine)[source](patches): New field.
[arguments]: Remove hard coded Python version from #:configure-flags.

gnu/local.mk

@@ -868,6 +868,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/fasthenry-spSolve.patch			\
   %D%/packages/patches/fasthenry-spFactor.patch			\
   %D%/packages/patches/fbreader-curl-7.62.patch		\
+  %D%/packages/patches/fifengine-swig-compat.patch		\
   %D%/packages/patches/fifo-map-fix-flags-for-gcc.patch		\
   %D%/packages/patches/fifo-map-remove-catch.hpp.patch		\
   %D%/packages/patches/findutils-localstatedir.patch		\

gnu/packages/games.scm

@@ -2280,6 +2280,7 @@ Widgets, and allows users to create more.")
               (uri (string-append "https://codeload.github.com/fifengine/"
                                   "fifengine/tar.gz/" version))
               (file-name (string-append name "-" version ".tar.gz"))
+              (patches (search-patches "fifengine-swig-compat.patch"))
               (sha256
                (base32
                 "1y4grw25cq5iqlg05rnbyxw1njl11ypidnlsm3qy4sm3xxdvb0p8"))))
@@ -2296,7 +2297,9 @@ Widgets, and allows users to create more.")
                        "/include/AL")
         (string-append "-DPYTHON_SITE_PACKAGES="
                        (assoc-ref %outputs "out")
-                       "/lib/python3.7/site-packages"))
+                       "/lib/python"
+                       ,(version-major+minor (package-version python))
+                       "/site-packages"))
        #:phases
        (modify-phases %standard-phases
          (add-after 'unpack 'patch-run_tests.py

gnu/packages/patches/fifengine-swig-compat.patch

@@ -0,0 +1,17 @@
+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})