diff --git a/Makefile b/Makefile
index b207257..16e01d0 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,5 @@
 CFLAGS=-fPIC
+CFLAGS+=-std=c11 -pedantic -Werror -Wformat
 
 # Debug flags
 #CFLAGS+=-fsanitize=address
diff --git a/dump.c b/dump.c
index f8caf2a..2341fec 100644
--- a/dump.c
+++ b/dump.c
@@ -43,7 +43,7 @@ void emit(struct ovni_stream *stream, struct ovni_ev *ev)
 
 	delta = clock - stream->lastclock;
 
-	printf("%d.%d.%d %c %c %c % 20lu % 15ld ",
+	printf("%d.%d.%d %c %c %c % 20ld % 15ld ",
 			stream->loom, stream->proc, stream->tid,
 			ev->header.model, ev->header.class, ev->header.value, clock, delta);
 
diff --git a/emu.c b/emu.c
index e50ad64..280712e 100644
--- a/emu.c
+++ b/emu.c
@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200112L
+
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
@@ -483,7 +485,11 @@ load_clock_offsets(struct ovni_emu *emu)
 	}
 
 	/* Ignore header line */
-	fgets(buf, 1024, f);
+	if(fgets(buf, 1024, f) == NULL)
+	{
+		perror("fgets failed");
+		exit(EXIT_FAILURE);
+	}
 
 	while(1)
 	{
diff --git a/ovni.c b/ovni.c
index f009b58..ce84bfc 100644
--- a/ovni.c
+++ b/ovni.c
@@ -9,7 +9,6 @@
 #include <linux/limits.h>
 #include <errno.h>
 #include <sys/stat.h>
-#include <sys/syscall.h>
 #include <sys/mman.h>
 #include <stdatomic.h>
 #include <assert.h>
@@ -22,6 +21,11 @@
 #include "ovni_trace.h"
 #include "parson.h"
 
+#ifndef gettid
+# include <sys/syscall.h>
+# define gettid() ((pid_t)syscall(SYS_gettid))
+#endif
+
 //#define ENABLE_SLOW_CHECKS
 
 //#define USE_RDTSC
@@ -69,7 +73,7 @@ create_trace_stream()
 	char path[PATH_MAX];
 
 	fprintf(stderr, "create thread stream tid=%d gettid=%d rproc.proc=%d rproc.ready=%d\n",
-			rthread.tid, syscall(SYS_gettid), rproc.proc, rproc.ready);
+			rthread.tid, gettid(), rproc.proc, rproc.ready);
 
 	snprintf(path, PATH_MAX, "%s/thread.%d", rproc.dir, rthread.tid);
 
@@ -294,7 +298,7 @@ uint64_t rdtsc(void)
     uint32_t lo, hi;
 
     // RDTSC copies contents of 64-bit TSC into EDX:EAX
-    asm volatile("rdtsc" : "=a" (lo), "=d" (hi));
+    __asm__ volatile("rdtsc" : "=a" (lo), "=d" (hi));
     return (uint64_t) hi << 32 | lo;
 }
 
@@ -782,7 +786,7 @@ load_stream_buf(struct ovni_stream *stream, struct ovni_ethread *thread)
 
 	if(st.st_size == 0)
 	{
-		err("warning: stream %s is empty\n", stream->tid);
+		err("warning: stream %d is empty\n", stream->tid);
 		stream->size = 0;
 		stream->buf = NULL;
 		stream->active = 0;
diff --git a/ovni.h b/ovni.h
index 8bf666b..9f7cc1f 100644
--- a/ovni.h
+++ b/ovni.h
@@ -6,6 +6,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <linux/limits.h>
+#include <sys/types.h>
 #include <limits.h>
 
 #include "parson.h"
diff --git a/ovnisync.c b/ovnisync.c
index 2ff3379..e8d2d14 100644
--- a/ovnisync.c
+++ b/ovnisync.c
@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200112L
+
 #include <limits.h>
 #include <time.h>
 #include <stdio.h>
@@ -6,6 +8,7 @@
 #include <math.h>
 #include <unistd.h>
 #include <assert.h>
+#include <time.h>
 
 #include "ovni.h"
 
@@ -400,7 +403,7 @@ do_work(struct options *options, int rank)
 		}
 
 		if(drift_mode)
-			usleep(options->drift_wait * 1000 * 1000);
+			sleep(options->drift_wait);
 	}
 }
 
diff --git a/test_speed.c b/test_speed.c
index cae40b9..53ff3b7 100644
--- a/test_speed.c
+++ b/test_speed.c
@@ -1,9 +1,13 @@
+#define _POSIX_C_SOURCE 200112L
+#define _GNU_SOURCE
+
 #include <stdint.h>
 #include <stddef.h>
 #include <stdio.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <linux/limits.h>
+#include <limits.h>
 
 #include "ovni.h"