meson: Simplify asan-options handling even more

Instead of specifying env variables all the time
we can instead embed the __asan_default_options symbol
in all executables / shared objects. This reduces code
duplication.

tests/functional/test-libstoreconsumer/main.cc

@@ -5,13 +5,6 @@
 
 using namespace nix;
 
-extern "C" [[gnu::retain]] const char * __asan_default_options()
-{
-    // We leak a bunch of memory knowingly on purpose. It's not worthwhile to
-    // diagnose that memory being leaked for now.
-    return "abort_on_error=1:print_summary=1:detect_leaks=0";
-}
-
 int main(int argc, char ** argv)
 {
     try {

tests/functional/test-libstoreconsumer/meson.build

@@ -1,11 +1,12 @@
 cxx = meson.get_compiler('cpp')
 
+deps_other = []
 subdir('nix-meson-build-support/common/asan-options')
 
 libstoreconsumer_tester = executable(
   'test-libstoreconsumer',
   'main.cc',
-  dependencies : [
+  dependencies : deps_other + [
     dependency('nix-store'),
   ],
   build_by_default : false,