meson: wire up fuzzers

Meson does not yet know to build our fuzzers. Introduce a new build
option "fuzzers" and wire up the fuzzers in case it is enabled. Adapt
our CI jobs so that they build the fuzzers by default.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

oss-fuzz/meson.build

@@ -0,0 +1,20 @@
+fuzz_programs = [
+  'fuzz-commit-graph.c',
+  'fuzz-config.c',
+  'fuzz-credential-from-url-gently.c',
+  'fuzz-date.c',
+  'fuzz-pack-headers.c',
+  'fuzz-pack-idx.c',
+  'fuzz-parse-attr-line.c',
+  'fuzz-url-decode-mem.c',
+]
+
+foreach fuzz_program : fuzz_programs
+  executable(fs.stem(fuzz_program),
+    sources: [
+      'dummy-cmd-main.c',
+      fuzz_program,
+    ],
+    dependencies: [libgit, common_main],
+  )
+endforeach