diff --git a/compat.h b/compat.h
new file mode 100644
index 0000000..1da332e
--- /dev/null
+++ b/compat.h
@@ -0,0 +1,40 @@
+/*
+ * MIT License
+ * 
+ * Copyright (c) 2022 Barcelona Supercomputing Center (BSC)
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef COMPAT_H
+#define COMPAT_H
+
+#define _GNU_SOURCE
+#include <sys/syscall.h>
+#include <unistd.h>
+
+/* Define gettid for older glibc versions (below 2.30) */
+#if defined(__GLIBC__) && !__GLIBC_PREREQ(2, 30)
+static inline pid_t gettid(void)
+{
+	return (pid_t)syscall(SYS_gettid);
+}
+#endif
+
+#endif // COMPAT_H
diff --git a/ovni.c b/ovni.c
index c675cec..170a83f 100644
--- a/ovni.c
+++ b/ovni.c
@@ -37,11 +37,7 @@
 #include "ovni.h"
 #include "common.h"
 #include "parson.h"
-
-#ifndef gettid
-# include <sys/syscall.h>
-# define gettid() ((pid_t)syscall(SYS_gettid))
-#endif
+#include "compat.h"
 
 /* Data per process */
 struct ovni_rproc rproc = {0};
diff --git a/test/flush.c b/test/flush.c
index 33b5a67..2b061e0 100644
--- a/test/flush.c
+++ b/test/flush.c
@@ -28,14 +28,7 @@
 #include <limits.h>
 
 #include "ovni.h"
-
-// Define gettid for older glibc versions (below 2.30)
-#if !__GLIBC_PREREQ(2, 30)
-static inline pid_t gettid(void)
-{
-	return (pid_t)syscall(SYS_gettid);
-}
-#endif
+#include "compat.h"
 
 static inline void
 init(void)
diff --git a/test/mp-rank.c b/test/mp-rank.c
index 9a3419b..569adc6 100644
--- a/test/mp-rank.c
+++ b/test/mp-rank.c
@@ -18,6 +18,7 @@
 #define _GNU_SOURCE
 
 #include "ovni.h"
+#include "compat.h"
 
 #include <assert.h>
 #include <inttypes.h>
diff --git a/test/mp-simple.c b/test/mp-simple.c
index 3d8a389..5c8dfe4 100644
--- a/test/mp-simple.c
+++ b/test/mp-simple.c
@@ -18,6 +18,7 @@
 #define _GNU_SOURCE
 
 #include "ovni.h"
+#include "compat.h"
 
 #include <assert.h>
 #include <inttypes.h>
diff --git a/test_speed.c b/test_speed.c
index b1280c5..3e42567 100644
--- a/test_speed.c
+++ b/test_speed.c
@@ -27,11 +27,7 @@
 #include <limits.h>
 
 #include "ovni.h"
-
-#ifndef gettid
-# include <sys/syscall.h>
-# define gettid() ((pid_t)syscall(SYS_gettid))
-#endif
+#include "compat.h"
 
 static inline void
 init(void)