rewrite fuzzer build logic and hook up atom parser fuzzer to fifos

fuzz/atom/vercmp/meson.build

@@ -1,7 +1,31 @@
-fuzzers += {
-    'atom_vercmp': {
-        'gencorpus': meson.current_source_dir() / 'gencorpus.rs',
-        'fuzzer': meson.current_source_dir() / 'fuzz.rs',
-        'deps': [mon],
-    },
-}
+gencorpus = executable(
+    'gencorpus',
+    'gencorpus.rs',
+    dependencies: [mon],
+    link_with: [gentoo_utils],
+)
+
+corpus = custom_target(
+    'corpus',
+    output: 'corpus',
+    command: [gencorpus, 'corpus'],
+)
+
+fuzz_rs = static_library(
+    'vercmp_fuzzer',
+    'fuzz.rs',
+    rust_abi: 'c',
+    rust_args: [
+        '-Cpasses=sancov-module',
+        '-Cllvm-args=-sanitizer-coverage-level=3',
+        '-Cllvm-args=-sanitizer-coverage-inline-8bit-counters',
+    ],
+    dependencies: [mon],
+    link_with: [gentoo_utils],
+)
+
+fuzz = executable(
+    'fuzzer',
+    link_args: ['-fsanitize=fuzzer'],
+    link_with: [fuzz_rs],
+)