diff --git a/Makefile b/Makefile
index bfa5b3a..ba4359e 100644
--- a/Makefile
+++ b/Makefile
@@ -1022,6 +1022,14 @@
 CFLAGS += $(DEVELOPER_CFLAGS)
 endif
 
+ifdef SANITIZE
+BASIC_CFLAGS += -fsanitize=$(SANITIZE) -fno-sanitize-recover=$(SANITIZE)
+BASIC_CFLAGS += -fno-omit-frame-pointer
+ifeq ($(SANITIZE),undefined)
+BASIC_CFLAGS += -DNO_UNALIGNED_LOADS
+endif
+endif
+
 ifndef sysconfdir
 ifeq ($(prefix),/usr)
 sysconfdir = /etc
diff --git a/t/test-lib.sh b/t/test-lib.sh
index 2306574..1b6e53f 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -36,6 +36,14 @@
 fi
 GIT_BUILD_DIR="$TEST_DIRECTORY"/..
 
+# If we were built with ASAN, it may complain about leaks
+# of program-lifetime variables. Disable it by default to lower
+# the noise level. This needs to happen at the start of the script,
+# before we even do our "did we build git yet" check (since we don't
+# want that one to complain to stderr).
+: ${ASAN_OPTIONS=detect_leaks=0:abort_on_error=1}
+export ASAN_OPTIONS
+
 ################################################################
 # It appears that people try to run tests without building...
 "$GIT_BUILD_DIR/git" >/dev/null
@@ -148,9 +156,6 @@
 	}
 fi
 
-: ${ASAN_OPTIONS=detect_leaks=0}
-export ASAN_OPTIONS
-
 # Protect ourselves from common misconfiguration to export
 # CDPATH into the environment
 unset CDPATH