diff --git a/Makefile b/Makefile
index a122176fb..5c61312b4 100644
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,8 @@ endif
 
 include $(TOPDIR)/Make.defs
 
-.PHONY: all clean libc kconfig defconfig config menuconfig image images kclean
+.PHONY: all clean libc kconfig defconfig config menuconfig image images \
+    kimage kernel kclean owc c86
 
 all: .config include/autoconf.h
 	$(MAKE) -C libc all
@@ -34,6 +35,8 @@ kclean:
 
 clean:
 	$(MAKE) -C libc clean
+	$(MAKE) -C libc -f watcom.mk clean
+	$(MAKE) -C libc -f c86.mk
 	$(MAKE) -C libc DESTDIR='$(TOPDIR)/cross' uninstall
 	$(MAKE) -C elks clean
 	$(MAKE) -C bootblocks clean
@@ -54,6 +57,14 @@ libc:
 	$(MAKE) -C libc all
 	$(MAKE) -C libc DESTDIR='$(TOPDIR)/cross' install
 
+owc:
+	$(MAKE) -C libc -f watcom.mk clean
+	$(MAKE) -C libc -f watcom.mk
+
+c86:
+	$(MAKE) -C libc -f c86.mk clean
+	$(MAKE) -C libc -f c86.mk
+
 elks/arch/i86/drivers/char/KeyMaps/config.in:
 	$(MAKE) -C elks/arch/i86/drivers/char/KeyMaps config.in
 
diff --git a/libc/include/watcom/_comdef.h b/libc/include/watcom/_comdef.h
new file mode 100644
index 000000000..0845d6457
--- /dev/null
+++ b/libc/include/watcom/_comdef.h
@@ -0,0 +1,198 @@
+/*
+ *  _comdef.h   Common Macro Definitions
+ *
+ * =========================================================================
+ *
+ *                          Open Watcom Project
+ *
+ * Copyright (c) 2004-2024 The Open Watcom Contributors. All Rights Reserved.
+ * Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
+ *
+ *    This file is automatically generated. Do not edit directly.
+ *
+ * =========================================================================
+ */
+#ifndef __COMDEF_H_INCLUDED
+#define __COMDEF_H_INCLUDED
+
+#ifndef _ENABLE_AUTODEPEND
+ #pragma read_only_file
+#endif
+
+ #ifdef _WCDATA
+  #error The macro _WCDATA is reserved for use by the runtime library.
+ #endif
+ #ifdef _WCNEAR
+  #error The macro _WCNEAR is reserved for use by the runtime library.
+ #endif
+ #ifdef _WCFAR
+  #error The macro _WCFAR is reserved for use by the runtime library.
+ #endif
+ #ifdef _WCHUGE
+  #error The macro _WCHUGE is reserved for use by the runtime library.
+ #endif
+ #ifdef _WCI86NEAR
+  #error The macro _WCI86NEAR is reserved for use by the runtime library.
+ #endif
+ #ifdef _WCI86FAR
+  #error The macro _WCI86FAR is reserved for use by the runtime library.
+ #endif
+ #ifdef _WCI86HUGE
+  #error The macro _WCI86HUGE is reserved for use by the runtime library.
+ #endif
+ #ifdef _WCINTERRUPT
+  #error The macro _WCINTERRUPT is reserved for use by the runtime library.
+ #endif
+ #ifdef _WCUNALIGNED
+  #error The macro _WCUNALIGNED is reserved for use by the runtime library.
+ #endif
+ #ifdef _WCNORETURN
+  #error The macro _WCNORETURN is reserved for use by the runtime library.
+ #endif
+ #ifdef _WCCALLBACK
+  #error The macro _WCCALLBACK is reserved for use by the runtime library.
+ #endif
+ #ifdef _WCHANDLER
+  #error The macro _WCHANDLER is reserved for use by the runtime library.
+ #endif
+ #define _WRTLFCONV __declspec(__watcall)
+ #define _WRTLDCONV __declspec(__watcall)
+ #ifdef _M_IX86
+  #define _WCCALLBACK __watcall
+  #define _WCNORETURN __declspec(aborts)
+  #define _WCNEAR __near
+  #define _WCFAR __far
+  #define _WCHUGE __huge
+  #define _WCINTERRUPT __interrupt
+  #define _WCUNALIGNED
+  #ifdef _M_I86
+   #define _WCI86NEAR __near
+   #define _WCI86FAR __far
+   #define _WCI86HUGE __huge
+  #else
+   #define _WCI86NEAR
+   #define _WCI86FAR
+   #define _WCI86HUGE
+  #endif
+ #elif defined(__AXP__)
+  #define _WCCALLBACK
+  #define _WCNORETURN __declspec(aborts)
+  #define _WCNEAR
+  #define _WCFAR
+  #define _WCHUGE
+  #define _WCI86NEAR
+  #define _WCI86FAR
+  #define _WCI86HUGE
+  #define _WCINTERRUPT
+  #define _WCUNALIGNED __unaligned
+ #elif defined(__PPC__)
+  #define _WCCALLBACK
+  #define _WCNORETURN __declspec(aborts)
+  #define _WCNEAR
+  #define _WCFAR
+  #define _WCHUGE
+  #define _WCI86NEAR
+  #define _WCI86FAR
+  #define _WCI86HUGE
+  #define _WCINTERRUPT
+  #define _WCUNALIGNED __unaligned
+ #elif defined(__MIPS__)
+  #define _WCCALLBACK
+  #define _WCNORETURN __declspec(aborts)
+  #define _WCNEAR
+  #define _WCFAR
+  #define _WCHUGE
+  #define _WCI86NEAR
+  #define _WCI86FAR
+  #define _WCI86HUGE
+  #define _WCINTERRUPT
+  #define _WCUNALIGNED __unaligned
+ #else
+  #define _WCCALLBACK
+  #define _WCNORETURN
+  #define _WCNEAR
+  #define _WCFAR
+  #define _WCHUGE
+  #define _WCI86NEAR
+  #define _WCI86FAR
+  #define _WCI86HUGE
+  #define _WCINTERRUPT
+  #define _WCUNALIGNED
+ #endif
+ #if defined( _M_I86 ) && defined( __HUGE__ )
+  #define _WCDATA _WCFAR
+ #elif defined(__SW_ND) || defined(__FUNCTION_DATA_ACCESS)
+  #define _WCDATA
+ #else
+  #define _WCDATA _WCNEAR
+ #endif
+ #ifdef __SW_BR
+  #ifdef __NT__
+   #define _WCRTLINK __declspec(dllimport) _WRTLFCONV
+   #define _WCRTDATA __declspec(dllimport) _WRTLDCONV
+   #define _WMRTLINK __declspec(dllimport) _WRTLFCONV
+   #define _WMRTDATA __declspec(dllimport) _WRTLDCONV
+   #define _WPRTLINK __declspec(dllimport) _WRTLFCONV
+   #define _WPRTDATA __declspec(dllimport) _WRTLDCONV
+   #define _WCHANDLER __declspec(dllimport) __declspec(_WCCALLBACK)
+  #else
+   #define _WCRTLINK _WRTLFCONV
+   #define _WCRTDATA _WRTLDCONV
+   #define _WMRTLINK _WRTLFCONV
+   #define _WMRTDATA _WRTLDCONV
+   #define _WPRTLINK _WRTLFCONV
+   #define _WPRTDATA _WRTLDCONV
+   #define _WCHANDLER __declspec(_WCCALLBACK)
+  #endif
+ #else
+  #ifndef _WCRTLINK
+   #define _WCRTLINK _WRTLFCONV
+  #endif
+  #ifndef _WCRTDATA
+   #define _WCRTDATA _WRTLDCONV
+  #endif
+  #ifndef _WMRTLINK
+   #define _WMRTLINK _WRTLFCONV
+  #endif
+  #ifndef _WMRTDATA
+   #define _WMRTDATA _WRTLDCONV
+  #endif
+  #ifndef _WPRTLINK
+   #define _WPRTLINK _WRTLFCONV
+  #endif
+  #ifndef _WPRTDATA
+   #define _WPRTDATA _WRTLDCONV
+  #endif
+  #ifndef _WCHANDLER
+   #define _WCHANDLER __declspec(_WCCALLBACK)
+  #endif
+ #endif
+ /* control import modifier on intrinsic functions */
+ #ifndef _WCIRTLINK
+  #ifdef __INLINE_FUNCTIONS__
+   #define _WCIRTLINK _WRTLFCONV
+  #else
+   #define _WCIRTLINK _WCRTLINK
+  #endif
+ #endif
+ #ifndef _WMIRTLINK
+  #if defined(__NO_MATH_OPS) || defined(__AXP__) || defined(__PPC__) || defined(__MIPS__)
+   #define _WMIRTLINK _WMRTLINK
+  #else
+   #define _WMIRTLINK _WRTLFCONV
+  #endif
+ #endif
+ #ifndef _WPIRTLINK
+  #define _WPIRTLINK _WPRTLINK
+ #endif
+ /* for MS compatibility */
+ #ifndef _CRTAPI1
+  #define _CRTAPI1
+ #endif
+ #ifndef _CRTAPI2
+  #define _CRTAPI2
+ #endif
+ #ifndef _CRTIMP
+  #define _CRTIMP _WCRTLINK
+ #endif
+#endif
diff --git a/libc/include/watcom/stdarg.h b/libc/include/watcom/stdarg.h
new file mode 100644
index 000000000..bbf471644
--- /dev/null
+++ b/libc/include/watcom/stdarg.h
@@ -0,0 +1,140 @@
+/***************************************************************************
+ * FILE: stdarg.h/cstdarg (Macros for use with variable argument lists)
+ *
+ * =========================================================================
+ *
+ *                          Open Watcom Project
+ *
+ * Copyright (c) 2004-2024 The Open Watcom Contributors. All Rights Reserved.
+ * Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
+ *
+ *    This file is automatically generated. Do not edit directly.
+ *
+ * =========================================================================
+ *
+ * Description: This header is part of the C/C++ standard library. It
+ *              contains macros for use in variable length argument
+ *              lists.
+ ***************************************************************************/
+#ifndef _STDARG_H_INCLUDED
+#define _STDARG_H_INCLUDED
+
+#ifndef _ENABLE_AUTODEPEND
+ #pragma read_only_file
+#endif
+
+#ifdef __cplusplus
+
+#include <cstdarg>
+
+using std::va_list;
+
+#else /* __cplusplus not defined */
+
+#ifndef __COMDEF_H_INCLUDED
+ #include <_comdef.h>
+#endif
+
+#ifndef ___VA_LIST_DEFINED
+#define ___VA_LIST_DEFINED
+ #ifdef __PPC__
+  #ifdef __NT__
+   typedef char  *__va_list;
+  #else
+   typedef struct {
+       char  __gpr;
+       char  __fpr;
+       char  __reserved[2];
+       char  *__input_arg_area;
+       char  *__reg_save_area;
+   } __va_list;
+  #endif
+ #elif defined(__AXP__)
+  typedef struct {
+      char  *__base;
+      int   __offset;
+  } __va_list;
+ #elif defined(__MIPS__)
+  typedef struct {
+      char  *__base;
+      int   __offset;
+  } __va_list;
+ #elif defined(_M_IX86)
+  #if defined(__HUGE__) || defined(__SW_ZU)
+   typedef char _WCFAR *__va_list;
+  #else
+   typedef char    *__va_list;
+  #endif
+ #endif
+#endif
+
+#ifndef _VA_LIST_DEFINED
+#define _VA_LIST_DEFINED
+  typedef __va_list va_list;
+#endif
+
+#ifdef __AXP__
+ #define _AXP_WORD_SIZE     8
+ #define _AXP_FLOAT_SIZE    8
+ #define _AXP_FLOAT_REGS    6
+ extern void *__builtin_va_start(__va_list*, ...);
+ #pragma intrinsic(__builtin_va_start)
+ #define va_start(__ap,__pn)    (__builtin_va_start(&__ap,__pn,1))
+ #define va_arg(__ap,__type)    ((__ap).__offset+=\
+     ((sizeof(__type)+_AXP_WORD_SIZE-1)&~(_AXP_WORD_SIZE-1)),\
+     (*(__type *)((__ap).__base+(__ap).__offset-\
+       ((__builtin_isfloat(__type)&&(__ap).__offset <=\
+         (_AXP_FLOAT_REGS*_AXP_FLOAT_SIZE)) ?\
+           (_AXP_FLOAT_REGS*_AXP_FLOAT_SIZE)+_AXP_FLOAT_SIZE :\
+             ((sizeof(__type)+_AXP_WORD_SIZE-1)&~(_AXP_WORD_SIZE-1))))))
+ #define va_end(__ap)           ((void)0)
+#elif defined(__PPC__)
+ #ifdef __NT__
+  #define _INTSIZEOF(__n)       ((sizeof(__n) + sizeof(int) - 1) & ~(sizeof(int) - 1))
+  #define _ALIGNIT(__ap,__t)    ((((int)(__ap))+(sizeof(__t)<8?3:7)) & (sizeof(__t)<8?~3:~7))
+  #define va_start(__ap,__v)    (__ap = (__va_list)&__v + _INTSIZEOF(__v))
+  #define va_arg(__ap,__t)      (*(__t *)((__ap = (char *)(_ALIGNIT(__ap,__t) + _INTSIZEOF(__t))) - _INTSIZEOF(__t)))
+  #define va_end(__ap)          (__ap = (__va_list)0)
+ #else
+  extern void *__builtin_va_start( __va_list *, ...);
+  #pragma intrinsic(__builtin_va_start)
+  #define va_start(__ap,__pn)   (__builtin_va_start(&__ap,__pn,1))
+  #define va_arg(__ap,__type)   (__builtin_va_arg(&__ap,__type))
+ #endif
+#elif defined(__MIPS__)
+ #define _MIPS_WORD_SIZE     4
+ extern void *__builtin_va_start(__va_list*, ...);
+ #pragma intrinsic(__builtin_va_start)
+ #define va_start(__ap,__pn)    (__builtin_va_start(&__ap,__pn,1))
+ #define va_arg(__ap,__type)    ((__ap).__offset+=\
+     ((sizeof(__type)+_MIPS_WORD_SIZE-1)&~(_MIPS_WORD_SIZE-1)),\
+     (*(__type *)((__ap).__base+(__ap).__offset-\
+       (((sizeof(__type)+_MIPS_WORD_SIZE-1)&~(_MIPS_WORD_SIZE-1))))))
+ #define va_end(__ap)           ((void)0)
+#elif defined(_M_IX86)
+ #if defined(__HUGE__) || defined(__SW_ZU)
+  #define va_start(__ap,__pn)   (__ap=(char _WCFAR*)&__pn+\
+      ((sizeof(__pn)+sizeof(int)-1)&~(sizeof(int)-1)),(void)0)
+  #define va_arg(__ap,__type)   (__ap+=\
+      ((sizeof(__type)+sizeof(int)-1)&~(sizeof(int)-1)),\
+      (*(__type _WCFAR*)(__ap-((sizeof(__type)+sizeof(int)-1)&~(sizeof(int)-1)))))
+  #define va_end(__ap)          (__ap=0,(void)0)
+ #else
+  #define va_start(__ap,__pn)   (__ap=(char *)&__pn+\
+      ((sizeof(__pn)+sizeof(int)-1)&~(sizeof(int)-1)),(void)0)
+  #define va_arg(__ap,__type)   (__ap+=\
+      ((sizeof(__type)+sizeof(int)-1)&~(sizeof(int)-1)),\
+      (*(__type *)(__ap-((sizeof(__type)+sizeof(int)-1)&~(sizeof(int)-1)))))
+  #define va_end(__ap)          (__ap=0,(void)0)
+ #endif
+#endif
+
+#define __va_copy(__dest,__src)    ((__dest)=(__src),(void)0)
+
+#if !defined( _NO_EXT_KEYS ) || __STDC_VERSION__ >= 199901L /* extensions enabled or C99 */
+#define va_copy(__dest,__src)   __va_copy(__dest,__src)
+#endif /* extensions enabled */
+
+#endif /* __cplusplus not defined */
+
+#endif
diff --git a/libc/include/watcom/stdbool.h b/libc/include/watcom/stdbool.h
new file mode 100644
index 000000000..8399c9eed
--- /dev/null
+++ b/libc/include/watcom/stdbool.h
@@ -0,0 +1,43 @@
+/***************************************************************************
+ * FILE: stdbool.h/cstdbool (Macros to simulate the 'bool' type in C)
+ *
+ * =========================================================================
+ *
+ *                          Open Watcom Project
+ *
+ * Copyright (c) 2004-2024 The Open Watcom Contributors. All Rights Reserved.
+ * Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
+ *
+ *    This file is automatically generated. Do not edit directly.
+ *
+ * =========================================================================
+ *
+ * Description: This header is part of the C99/C++ standard library. It
+ *              provides a way for the programmer, at his/her option
+ *              to introduce the type 'bool' into a C program.
+ ***************************************************************************/
+#ifndef _STDBOOL_H_INCLUDED
+#define _STDBOOL_H_INCLUDED
+
+#ifndef _ENABLE_AUTODEPEND
+ #pragma read_only_file
+#endif
+
+#ifdef __cplusplus
+
+#include <cstdbool>
+
+#else /* __cplusplus not defined */
+
+ #define bool _Bool
+ #define true  1
+ #define false 0
+ #if __STDC_VERSION__ < 199901L
+  typedef unsigned char _Bool;
+ #endif
+
+ #define __bool_true_false_are_defined 1
+
+#endif /* __cplusplus not defined */
+
+#endif
diff --git a/libc/watcom.inc b/libc/watcom.inc
index 3f33c2036..a4ccbb0e5 100644
--- a/libc/watcom.inc
+++ b/libc/watcom.inc
@@ -9,7 +9,11 @@ $(error WATCOM environment variable not set)
 endif
 
 INCLUDES = -I$(TOPDIR)/libc/include -I$(TOPDIR)/elks/include
-INCLUDES += -I$(WATCOM)/h
+# Watcom headers now included in libc/include/watcom
+INCLUDES += -I$(TOPDIR)/libc/include/watcom
+# Don't pull in headers from Watcom installation
+#INCLUDES += -I$(WATCOM)/h
+
 DEFINES = -D__LIBC__
 LIBOBJS=$(OBJS:.o=.obj)