diff --git a/libguile/array-handle.c b/libguile/array-handle.c
index cbff8428f..e8d33d9ed 100644
--- a/libguile/array-handle.c
+++ b/libguile/array-handle.c
@@ -24,6 +24,8 @@
 #  include <config.h>
 #endif
 
+#include <string.h>
+
 #include "libguile/_scm.h"
 #include "libguile/__scm.h"
 #include "libguile/bitvectors.h"
diff --git a/libguile/array-map.c b/libguile/array-map.c
index ff5283aff..10ffee702 100644
--- a/libguile/array-map.c
+++ b/libguile/array-map.c
@@ -26,6 +26,8 @@
 # include <config.h>
 #endif
 
+#include <string.h>
+
 #include "libguile/_scm.h"
 #include "libguile/pairs.h"
 #include "libguile/boolean.h"
diff --git a/libguile/chars.c b/libguile/chars.c
index 9091d8693..2c5551b14 100644
--- a/libguile/chars.c
+++ b/libguile/chars.c
@@ -25,6 +25,7 @@
 
 #include <ctype.h>
 #include <limits.h>
+#include <string.h>
 #include <unicase.h>
 #include <unictype.h>
 
diff --git a/libguile/hash.c b/libguile/hash.c
index 35588acdb..8172f8f65 100644
--- a/libguile/hash.c
+++ b/libguile/hash.c
@@ -28,6 +28,7 @@
 #endif
 
 #include <math.h>
+#include <string.h>
 #include <unistr.h>
 
 #include "libguile/_scm.h"
diff --git a/libguile/memoize.c b/libguile/memoize.c
index 73de9b554..f85ebf50f 100644
--- a/libguile/memoize.c
+++ b/libguile/memoize.c
@@ -24,6 +24,8 @@
 #  include <config.h>
 #endif
 
+#include <string.h>
+
 #include "libguile/__scm.h"
 #include "libguile/pairs.h"
 #include "libguile/boolean.h"
diff --git a/libguile/ports-internal.h b/libguile/ports-internal.h
index 52a73b1bb..01c08e610 100644
--- a/libguile/ports-internal.h
+++ b/libguile/ports-internal.h
@@ -24,6 +24,7 @@
 
 #include <assert.h>
 #include <iconv.h>
+#include <string.h>
 
 #include "libguile/_scm.h"
 #include "libguile/bytevectors.h"
diff --git a/libguile/ports.h b/libguile/ports.h
index 54f9cbd69..bceac299e 100644
--- a/libguile/ports.h
+++ b/libguile/ports.h
@@ -27,7 +27,6 @@
 #include "libguile/__scm.h"
 
 #include <stdio.h>
-#include <string.h>
 #include <unistd.h>
 #include "libguile/gc.h"
 #include "libguile/tags.h"
diff --git a/libguile/regex-posix.c b/libguile/regex-posix.c
index 1cf45755b..3451b9b8a 100644
--- a/libguile/regex-posix.c
+++ b/libguile/regex-posix.c
@@ -32,6 +32,7 @@
 #  include <config.h>
 #endif
 
+#include <string.h>
 #include <sys/types.h>
 
 #include "libguile/_scm.h"
diff --git a/libguile/srfi-4.c b/libguile/srfi-4.c
index a1e2f65ea..fffad4884 100644
--- a/libguile/srfi-4.c
+++ b/libguile/srfi-4.c
@@ -22,6 +22,8 @@
 #  include <config.h>
 #endif
 
+#include <string.h>
+
 #include "libguile/_scm.h"
 #include "libguile/boolean.h"
 #include "libguile/__scm.h"
diff --git a/libguile/unicode.c b/libguile/unicode.c
index 628300e75..37eb57c56 100644
--- a/libguile/unicode.c
+++ b/libguile/unicode.c
@@ -22,6 +22,7 @@
 
 #include <ctype.h>
 #include <limits.h>
+#include <string.h>
 #include <unicase.h>
 #include <unictype.h>
 #include <uniname.h>
diff --git a/libguile/weak-set.c b/libguile/weak-set.c
index 7a4d8dab1..1206dfde6 100644
--- a/libguile/weak-set.c
+++ b/libguile/weak-set.c
@@ -23,6 +23,7 @@
 #endif
 
 #include <assert.h>
+#include <string.h>
 
 #include "libguile/_scm.h"
 #include "libguile/pairs.h"
diff --git a/libguile/weak-vector.c b/libguile/weak-vector.c
index 4c2f15dd5..f7305c05b 100644
--- a/libguile/weak-vector.c
+++ b/libguile/weak-vector.c
@@ -24,6 +24,7 @@
 #endif
 
 #include <stdio.h>
+#include <string.h>
 
 #include "libguile/_scm.h"
 #include "libguile/extensions.h"