treewide: Various fixes for clang compilation

Change-Id: I37e53e3854687ffeb146db515c2de69b2e6ac02d
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/test/fd/fmt.cpp b/test/fd/fmt.cpp
index 770bc99..9448fed 100644
--- a/test/fd/fmt.cpp
+++ b/test/fd/fmt.cpp
@@ -15,7 +15,6 @@
 namespace fd
 {
 
-using fmt::operator""_cf;
 using std::literals::string_view_literals::operator""sv;
 
 TEST(FormatBuffer, Basic)
@@ -31,7 +30,7 @@
         EXPECT_EQ(6, fd.lseek(0, Whence::Cur));
         buf.append(FMT_COMPILE("{}"), std::string(2050, 'a'));
         EXPECT_EQ(6, fd.lseek(0, Whence::Cur));
-        buf.append("{}"_cf, std::string(2050, 'a'));
+        buf.append(FMT_COMPILE("{}"), std::string(2050, 'a'));
         EXPECT_EQ(4106, fd.lseek(0, Whence::Cur));
 
         buf.append(FMT_STRING("hi\n"));
diff --git a/test/meson.build b/test/meson.build
index 01104c5..8403e0f 100644
--- a/test/meson.build
+++ b/test/meson.build
@@ -98,6 +98,7 @@
         t.underscorify(), t + '.cpp',
         build_by_default: false,
         implicit_include_directories: false,
+        cpp_args: '-Wno-missing-braces',
         dependencies: deps))
   endforeach
 endif
diff --git a/test/pinned.cpp b/test/pinned.cpp
index 5e58dc4..dd83375 100644
--- a/test/pinned.cpp
+++ b/test/pinned.cpp
@@ -104,8 +104,8 @@
     PinnedRef<const NoMove3> rnm3c(nm3);
     PinnedRef<const NoMove3> rnm3cr(rnm3);
     PinnedRef rnm3i(nm3);
-    PinnedRef rnm3ir(rnm3);
-    PinnedRef rnm3ic(rnm3c);
+    [[maybe_unused]] PinnedRef rnm3ir(rnm3);
+    [[maybe_unused]] PinnedRef rnm3ic(rnm3c);
 
     const NoMove3 cnm3;
     // PinnedRef<NoMove3> crnm3(cnm3);