build: better way to compile tyfuzz/tytest

meson.build

@@ -109,7 +109,6 @@ endif
 fuzzing = get_option('fuzzing')
 
 if fuzzing
-  config_data.set('ENABLE_FUZZING', 1)
   message('Fuzzing is enabled')
 else
   message('Fuzzing is disabled')
@@ -117,7 +116,6 @@ endif
 
 tests = get_option('tests')
 if tests
-  config_data.set('ENABLE_TESTS', 1)
   message('Tests are enabled')
 else
   message('Tests are disabled')

src/bin/meson.build

@@ -116,6 +116,7 @@ if fuzzing
              tyfuzz_sources,
              install: true,
              include_directories: config_dir,
+             c_args: '-DENABLE_FUZZING=1',
              dependencies: terminology_dependencies)
 endif
 if tests
@@ -123,5 +124,6 @@ if tests
              tytest_sources,
              install: true,
              include_directories: config_dir,
+             c_args: '-DENABLE_TESTS=1',
              dependencies: terminology_dependencies)
 endif