diff --git a/AK/String.h b/AK/String.h
index acf996661ca..885f30e8baa 100644
--- a/AK/String.h
+++ b/AK/String.h
@@ -30,7 +30,8 @@ class StringData;
 }
 
 // FIXME: Remove this when OpenBSD Clang fully supports consteval.
-#if defined(AK_OS_OPENBSD)
+//        And once oss-fuzz updates to clang >15.
+#if defined(AK_OS_OPENBSD) || defined(OSS_FUZZ)
 #    define AK_SHORT_STRING_CONSTEVAL constexpr
 #else
 #    define AK_SHORT_STRING_CONSTEVAL consteval
diff --git a/Meta/Lagom/BuildFuzzers.sh b/Meta/Lagom/BuildFuzzers.sh
index 96496d50aaa..4140758909e 100755
--- a/Meta/Lagom/BuildFuzzers.sh
+++ b/Meta/Lagom/BuildFuzzers.sh
@@ -46,10 +46,15 @@ unset CFLAGS
 unset CXXFLAGS
 export AFL_NOOPT=1
 
+if [ "$#" -gt "0" ] && [ "--oss-fuzz" = "$1" ] ; then
+    CXXFLAGS="$CXXFLAGS -DOSS_FUZZ=ON"
+fi
+
 # FIXME: Replace these CMake invocations with a CMake superbuild?
 echo "Building Lagom Tools..."
 cmake -GNinja -B Build/tools \
     -DBUILD_LAGOM=OFF \
+    -DCMAKE_CXX_FLAGS="$CXXFLAGS" \
     -DCMAKE_INSTALL_PREFIX=Build/tool-install \
     -Dpackage=LagomTools
 ninja -C Build/tools install