diff --git a/build.ninja b/build.ninja
index ddc17ea..770c94c 100644
--- a/build.ninja
+++ b/build.ninja
@@ -10,6 +10,7 @@
 subninja build/clang.portable
 subninja build/clang.tiny
 subninja build/clang.xsan
+subninja build/clang.xsan-portable
 
 subninja build/gcc
 subninja build/gcc.avx512
diff --git a/build/clang.xsan-portable b/build/clang.xsan-portable
new file mode 100644
index 0000000..f0ccef7
--- /dev/null
+++ b/build/clang.xsan-portable
@@ -0,0 +1,6 @@
+mode          = .xsan-portable
+extra_cflags  = -fsanitize=address,undefined -fno-sanitize-recover=all -DSKCMS_PORTABLE
+extra_ldflags = -fsanitize=address,undefined
+include build/clang
+
+# TODO: add -fsanitize=integer