diff --git a/.waf-tools/default-compiler-flags.py b/.waf-tools/default-compiler-flags.py
index 3e001a9..bac1893 100644
--- a/.waf-tools/default-compiler-flags.py
+++ b/.waf-tools/default-compiler-flags.py
@@ -11,7 +11,7 @@
     conf.start_msg('Checking C++ compiler version')
 
     cxx = conf.env.CXX_NAME # generic name of the compiler
-    ccver = tuple(int(i) for i in conf.env.CC_VERSION)
+    ccver = get_compiler_ver(conf)
     ccverstr = '.'.join(conf.env.CC_VERSION)
     errmsg = ''
     warnmsg = ''
@@ -60,6 +60,10 @@
     conf.env.DEFINES += generalFlags['DEFINES']
 
 
+def get_compiler_ver(conf):
+    return tuple(int(i) for i in conf.env.CC_VERSION)
+
+
 @Configure.conf
 def check_compiler_flags(conf):
     # Debug or optimized CXXFLAGS and LINKFLAGS are applied only if the
@@ -124,9 +128,6 @@
 
 
 class CompilerFlags:
-    def getCompilerVersion(self, conf):
-        return tuple(int(i) for i in conf.env.CC_VERSION)
-
     def getGeneralFlags(self, conf):
         """Get dict of CXXFLAGS, LINKFLAGS, and DEFINES that are always needed"""
         return {'CXXFLAGS': [], 'LINKFLAGS': [], 'DEFINES': []}
@@ -136,7 +137,7 @@
         return {
             'CXXFLAGS': [],
             'LINKFLAGS': [],
-            'DEFINES': ['BOOST_ASIO_NO_DEPRECATED', 'BOOST_FILESYSTEM_NO_DEPRECATED'],
+            'DEFINES': ['BOOST_ASIO_NO_DEPRECATED'],
         }
 
     def getOptimizedFlags(self, conf):
@@ -227,7 +228,7 @@
         elif Utils.unversioned_sys_platform() == 'freebsd':
             # Bug #4790
             flags['CXXFLAGS'] += [['-isystem', '/usr/local/include']]
-        if self.getCompilerVersion(conf) >= (18, 0, 0):
+        if get_compiler_ver(conf) >= (18, 0, 0) and get_compiler_ver(conf) < (20, 1, 0):
             # Bug #5300
             flags['CXXFLAGS'] += ['-Wno-enum-constexpr-conversion']
         return flags
@@ -241,10 +242,10 @@
         flags = super().getDebugFlags(conf)
         flags['CXXFLAGS'] += self.__cxxFlags
         # Enable assertions in libc++
-        if self.getCompilerVersion(conf) >= (18, 0, 0):
+        if get_compiler_ver(conf) >= (18, 0, 0):
             # https://libcxx.llvm.org/Hardening.html
             flags['DEFINES'] += ['_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_EXTENSIVE']
-        elif self.getCompilerVersion(conf) >= (15, 0, 0):
+        elif get_compiler_ver(conf) >= (15, 0, 0):
             # https://releases.llvm.org/15.0.0/projects/libcxx/docs/UsingLibcxx.html#enabling-the-safe-libc-mode
             flags['DEFINES'] += ['_LIBCPP_ENABLE_ASSERTIONS=1']
         # Tell libc++ to avoid including transitive headers