all .h: s/<(...)[.]h>/"\1.h"/

so that if the directory is not in the --include list, they can
include each other.

ctl/deq.h:
ctl/lst.h:
ctl/pqu.h:
ctl/que.h:
ctl/set.h:
ctl/stk.h:
ctl/str.h:
ctl/ust.h:
ctl/vec.h:

apparently there are arguments on both sides:

https://stackoverflow.com/a/72065059/1527747

isocpp/CppCoreGuidelines#1596 (comment)

Author: Greg Minshall

ctl/deq.h

@@ -6,7 +6,7 @@
 #error "Template type T undefined for <deq.h>"
 #endif
 
-#include <ctl.h>
+#include "ctl.h"
 
 #define A JOIN(deq, T)
 #define B JOIN(A, bucket)

ctl/lst.h

@@ -6,7 +6,7 @@
 #error "Template type T undefined for <lst.h>"
 #endif
 
-#include <ctl.h>
+#include "ctl.h"
 
 #define A JOIN(lst, T)
 #define B JOIN(A, node)

ctl/pqu.h

@@ -34,7 +34,7 @@
 #define HOLD
 #define COMPARE
 #define init __INIT
-#include <vec.h>
+#include "vec.h"
 #undef init
 #undef vec
 

ctl/que.h

@@ -26,7 +26,7 @@
 #define remove_if   __REMOVE_IF
 
 #define deq que
-#include <deq.h>
+#include "deq.h"
 #undef deq
 
 #undef push_back

ctl/set.h

@@ -6,7 +6,7 @@
 #error "Template type T undefined for <set.h>"
 #endif
 
-#include <ctl.h>
+#include "ctl.h"
 
 #define A JOIN(set, T)
 #define B JOIN(A, node)

ctl/stk.h

@@ -28,7 +28,7 @@
 #define remove_if   __REMOVE_IF
 
 #define deq stk
-#include <deq.h>
+#include "deq.h"
 #undef deq
 
 #undef push_back

ctl/str.h

@@ -16,7 +16,7 @@
 #define str_equal str___EQUAL
 #define str_find str___FIND
 #define str_copy str___COPY
-#include <vec.h>
+#include "vec.h"
 #undef str_init
 #undef str_copy
 #undef str_equal

ctl/ust.h

@@ -6,7 +6,7 @@
 #error "Template type T undefined for <ust.h>"
 #endif
 
-#include <ctl.h>
+#include "ctl.h"
 
 #define A JOIN(ust, T)
 #define B JOIN(A, node)

ctl/vec.h

@@ -6,7 +6,7 @@
 #error "Template type T undefined for <vec.h>"
 #endif
 
-#include <ctl.h>
+#include "ctl.h"
 
 #define A JOIN(vec, T)
 #define Z JOIN(A, it)