14 files changed, 28 insertions, 18 deletions
diff --git a/lib/libc/ctype/isalnum.c b/lib/libc/ctype/isalnum.c
index 3384aa56..3263f693 100644
--- a/lib/libc/ctype/isalnum.c
+++ b/lib/libc/ctype/isalnum.c
@@ -1,5 +1,8 @@
-#include <libc.h>
-#include <ctype.h>
+#include "features.h" // for __weak
+
+#include <ctype.h>  // for isalnum, isalpha, isdigit, isalnum_l
+#include <libc.h>   // for __unused
+#include <locale.h> // for locale_t
 
 int isalnum(int c)
 {
diff --git a/lib/libc/ctype/isalpha.c b/lib/libc/ctype/isalpha.c
index d046c09e..a1b89762 100644
--- a/lib/libc/ctype/isalpha.c
+++ b/lib/libc/ctype/isalpha.c
@@ -1,4 +1,4 @@
-#include <libc.h>
+#include <libc.h> // for weak_reference
 
 int isalpha(int c)
 {
diff --git a/lib/libc/ctype/isblank.c b/lib/libc/ctype/isblank.c
index 7ad08709..c4dacfb2 100644
--- a/lib/libc/ctype/isblank.c
+++ b/lib/libc/ctype/isblank.c
@@ -1,4 +1,4 @@
-#include <libc.h>
+#include <libc.h> // for weak_reference
 
 int isblank(int c)
 {
diff --git a/lib/libc/ctype/iscntrl.c b/lib/libc/ctype/iscntrl.c
index 6d4ff5a8..c25773b6 100644
--- a/lib/libc/ctype/iscntrl.c
+++ b/lib/libc/ctype/iscntrl.c
@@ -1,4 +1,4 @@
-#include <libc.h>
+#include <libc.h> // for weak_reference
 
 int iscntrl(int c)
 {
diff --git a/lib/libc/ctype/isdigit.c b/lib/libc/ctype/isdigit.c
index 445e1cdc..fa36222d 100644
--- a/lib/libc/ctype/isdigit.c
+++ b/lib/libc/ctype/isdigit.c
@@ -1,4 +1,4 @@
-#include <libc.h>
+#include <libc.h> // for weak_reference
 
 int isdigit(int c)
 {
diff --git a/lib/libc/ctype/isgraph.c b/lib/libc/ctype/isgraph.c
index 03919200..07df57d0 100644
--- a/lib/libc/ctype/isgraph.c
+++ b/lib/libc/ctype/isgraph.c
@@ -1,4 +1,4 @@
-#include <libc.h>
+#include <libc.h> // for weak_reference
 
 int isgraph(int c)
 {
diff --git a/lib/libc/ctype/islower.c b/lib/libc/ctype/islower.c
index 34980da6..a6108e39 100644
--- a/lib/libc/ctype/islower.c
+++ b/lib/libc/ctype/islower.c
@@ -1,4 +1,4 @@
-#include <libc.h>
+#include <libc.h> // for weak_reference
 
 int islower(int c)
 {
diff --git a/lib/libc/ctype/isprint.c b/lib/libc/ctype/isprint.c
index 76524050..dbd381e7 100644
--- a/lib/libc/ctype/isprint.c
+++ b/lib/libc/ctype/isprint.c
@@ -1,4 +1,4 @@
-#include <libc.h>
+#include <libc.h> // for weak_reference
 
 int isprint(int c)
 {
diff --git a/lib/libc/ctype/ispunct.c b/lib/libc/ctype/ispunct.c
index 24627809..e0029757 100644
--- a/lib/libc/ctype/ispunct.c
+++ b/lib/libc/ctype/ispunct.c
@@ -1,5 +1,8 @@
-#include <libc.h>
-#include <ctype.h>
+#include "features.h" // for __weak
+
+#include <ctype.h>  // for isalnum, isgraph, ispunct, ispunct_l
+#include <libc.h>   // for __unused
+#include <locale.h> // for locale_t
 
 int ispunct(int c)
 {
diff --git a/lib/libc/ctype/isspace.c b/lib/libc/ctype/isspace.c
index 86630c66..468e755b 100644
--- a/lib/libc/ctype/isspace.c
+++ b/lib/libc/ctype/isspace.c
@@ -1,4 +1,4 @@
-#include <libc.h>
+#include <libc.h> // for weak_reference
 
 int isspace(int c)
 {
diff --git a/lib/libc/ctype/isupper.c b/lib/libc/ctype/isupper.c
index 458990df..b46dce41 100644
--- a/lib/libc/ctype/isupper.c
+++ b/lib/libc/ctype/isupper.c
@@ -1,4 +1,4 @@
-#include <libc.h>
+#include <libc.h> // for weak_reference
 
 int isupper(int c)
 {
diff --git a/lib/libc/ctype/isxdigit.c b/lib/libc/ctype/isxdigit.c
index 588df77a..90346190 100644
--- a/lib/libc/ctype/isxdigit.c
+++ b/lib/libc/ctype/isxdigit.c
@@ -1,4 +1,4 @@
-#include <ctype.h>
+#include <ctype.h> // for isdigit, isxdigit
 
 int isxdigit(int c)
 {
diff --git a/lib/libc/ctype/tolower.c b/lib/libc/ctype/tolower.c
index aeb462d8..af196d05 100644
--- a/lib/libc/ctype/tolower.c
+++ b/lib/libc/ctype/tolower.c
@@ -1,5 +1,8 @@
-#include <libc.h>
-#include <ctype.h>
+#include "features.h" // for __weak
+
+#include <ctype.h>  // for isupper, tolower, tolower_l
+#include <libc.h>   // for __unused
+#include <locale.h> // for locale_t
 
 int tolower(int c)
 {
diff --git a/lib/libc/ctype/toupper.c b/lib/libc/ctype/toupper.c
index 934841fa..3f7ebf43 100644
--- a/lib/libc/ctype/toupper.c
+++ b/lib/libc/ctype/toupper.c
@@ -1,5 +1,6 @@
-#include <libc.h>
-#include <ctype.h>
+#include <ctype.h>  // for islower, toupper, toupper_l
+#include <libc.h>   // for __unused
+#include <locale.h> // for locale_t
 
 int toupper(int c)
 {