diff --git a/usr.bin/dtc/checking.cc b/usr.bin/dtc/checking.cc
index aff375225072..5462a494f888 100644
--- a/usr.bin/dtc/checking.cc
+++ b/usr.bin/dtc/checking.cc
@@ -31,6 +31,7 @@
  */
 
 #include "checking.hh"
+#include <stdio.h>
 
 namespace dtc
 {
diff --git a/usr.bin/dtc/dtb.cc b/usr.bin/dtc/dtb.cc
index 82ccc4778436..986ef6f717b5 100644
--- a/usr.bin/dtc/dtb.cc
+++ b/usr.bin/dtc/dtb.cc
@@ -31,7 +31,11 @@
  */
 
 #include "dtb.hh"
+#include <sys/types.h>
 #include <inttypes.h>
+#include <stdio.h>
+#include <unistd.h>
+
 
 namespace dtc
 {
diff --git a/usr.bin/dtc/dtc.cc b/usr.bin/dtc/dtc.cc
index bf52813bf49b..cffb3eb3cc32 100644
--- a/usr.bin/dtc/dtc.cc
+++ b/usr.bin/dtc/dtc.cc
@@ -31,10 +31,14 @@
  */
 
 #include <sys/resource.h>
-#include <time.h>
-#include <stdio.h>
 #include <fcntl.h>
 #include <libgen.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+
 
 #include "fdt.hh"
 #include "checking.hh"
diff --git a/usr.bin/dtc/fdt.cc b/usr.bin/dtc/fdt.cc
index 70b7d451129f..b6e7d56d7e44 100644
--- a/usr.bin/dtc/fdt.cc
+++ b/usr.bin/dtc/fdt.cc
@@ -33,9 +33,13 @@
 #include "fdt.hh"
 
 #include <algorithm>
-#include <inttypes.h>
+#include <ctype.h>
 #include <fcntl.h>
+#include <inttypes.h>
 #include <libgen.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
 #include "dtb.hh"
 
 namespace dtc
diff --git a/usr.bin/dtc/input_buffer.cc b/usr.bin/dtc/input_buffer.cc
index cd08dd394ab6..2a483f328646 100644
--- a/usr.bin/dtc/input_buffer.cc
+++ b/usr.bin/dtc/input_buffer.cc
@@ -31,8 +31,13 @@
  */
 
 #include "input_buffer.hh"
-#include <string.h>
+#include <ctype.h>
+#include <limits.h>
 #include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
 
 #include <sys/stat.h>
 #include <sys/mman.h>
diff --git a/usr.bin/dtc/string.cc b/usr.bin/dtc/string.cc
index 2f617cc8e9e8..283bafab2f69 100644
--- a/usr.bin/dtc/string.cc
+++ b/usr.bin/dtc/string.cc
@@ -31,6 +31,8 @@
  */
 
 #include "string.hh"
+#include <ctype.h>
+#include <stdio.h>
 
 namespace
 {