[build] Move headers out of target dirs

The great header shift: It didn't make sense to regenerate headers for
the same module for every target (boot/kernel/user) it appeared in. And
now that core headers are out of src/include, this was going to cause
problems for the new libc changes I've been working on. So I went back
to re-design how module headers work.

Pre-requisites:
- A module's public headers should all be available in one location, not
  tied to target.
- No accidental includes. Another module should not be able to include
  anything (creating an implicit dependency) from a module without
  declaring an explicit dependency.
- Exception to the previous: libc's headers should be available to all,
  at least for the freestanding headers.

New system:
- A new "public_headers" property of module declares all public headers
  that should be available to dependant modules
- All public headers (after possible processing) are installed relative
  to build/include/<module> with the same path as their source
- This also means no "include" dir in modules is necessary. If a header
  should be included as <j6/types.h> then its source should be
  src/libraries/j6/j6/types.h - this caused the most churn as all public
  header sources moved one directory up.
- The "includes" property of a module is local only to that module now,
  it does not create any implicit public interface

Other changes:
- The bonnibel concept of sources changed: instead of sources having
  actions, they themselves are an instance of a (sub)class of Source,
  which provides all the necessary information itself.
- Along with the above, rule names were standardized into <type>.<ext>,
  eg "compile.cpp" or "parse.cog"
- cog and cogflags variables moved from per-target scope to global scope
  in the build files.
- libc gained a more dynamic .module file

src/libraries/libc/locale.h

@@ -0,0 +1,96 @@
+#pragma once
+/* Localization <locale.h>
+
+   This file is part of the Public Domain C Library (PDCLib).
+   Permission is granted to use, modify, and / or redistribute at will.
+*/
+
+#include "j6libc/cpp.h"
+#include "j6libc/int.h"
+#include "j6libc/null.h"
+
+CPP_CHECK_BEGIN
+
+/* The structure returned by localeconv().
+
+   The values for *_sep_by_space:
+   0 - no space
+   1 - if symbol and sign are adjacent, a space seperates them from the value;
+       otherwise a space seperates the symbol from the value
+   2 - if symbol and sign are adjacent, a space seperates them; otherwise a
+       space seperates the sign from the value
+
+   The values for *_sign_posn:
+   0 - Parentheses surround value and symbol
+   1 - sign precedes value and symbol
+   2 - sign succeeds value and symbol
+   3 - sign immediately precedes symbol
+   4 - sign immediately succeeds symbol
+*/
+struct lconv
+{
+    char * decimal_point;      /* decimal point character                     */ /* LC_NUMERIC */
+    char * thousands_sep;      /* character for seperating groups of digits   */ /* LC_NUMERIC */
+    char * grouping;           /* string indicating the size of digit groups  */ /* LC_NUMERIC */
+    char * mon_decimal_point;  /* decimal point for monetary quantities       */ /* LC_MONETARY */
+    char * mon_thousands_sep;  /* thousands_sep for monetary quantities       */ /* LC_MONETARY */
+    char * mon_grouping;       /* grouping for monetary quantities            */ /* LC_MONETARY */
+    char * positive_sign;      /* string indicating nonnegative mty. qty.     */ /* LC_MONETARY */
+    char * negative_sign;      /* string indicating negative mty. qty.        */ /* LC_MONETARY */
+    char * currency_symbol;    /* local currency symbol (e.g. '$')            */ /* LC_MONETARY */
+    char * int_curr_symbol;    /* international currency symbol (e.g. "USD"   */ /* LC_MONETARY */
+    char frac_digits;          /* fractional digits in local monetary qty.    */ /* LC_MONETARY */
+    char p_cs_precedes;        /* if currency_symbol precedes positive qty.   */ /* LC_MONETARY */
+    char n_cs_precedes;        /* if currency_symbol precedes negative qty.   */ /* LC_MONETARY */
+    char p_sep_by_space;       /* if it is seperated by space from pos. qty.  */ /* LC_MONETARY */
+    char n_sep_by_space;       /* if it is seperated by space from neg. qty.  */ /* LC_MONETARY */
+    char p_sign_posn;          /* positioning of positive_sign for mon. qty.  */ /* LC_MONETARY */
+    char n_sign_posn;          /* positioning of negative_sign for mon. qty.  */ /* LC_MONETARY */
+    char int_frac_digits;      /* Same as above, for international format     */ /* LC_MONETARY */
+    char int_p_cs_precedes;    /* Same as above, for international format     */ /* LC_MONETARY */
+    char int_n_cs_precedes;    /* Same as above, for international format     */ /* LC_MONETARY */
+    char int_p_sep_by_space;   /* Same as above, for international format     */ /* LC_MONETARY */
+    char int_n_sep_by_space;   /* Same as above, for international format     */ /* LC_MONETARY */
+    char int_p_sign_posn;      /* Same as above, for international format     */ /* LC_MONETARY */
+    char int_n_sign_posn;      /* Same as above, for international format     */ /* LC_MONETARY */
+};
+
+/* First arguments to setlocale().
+   NOTE: If you add to / modify these, look at functions/locale/setlocale.c
+         and keep things in sync.
+*/
+/* Entire locale */
+#define LC_ALL      _PDCLIB_LC_ALL
+/* Collation (strcoll(), strxfrm()) */
+#define LC_COLLATE  _PDCLIB_LC_COLLATE
+/* Character types (<ctype.h>, <wctype.h>) */
+#define LC_CTYPE    _PDCLIB_LC_CTYPE
+/* Monetary formatting (as returned by localeconv) */
+#define LC_MONETARY _PDCLIB_LC_MONETARY
+/* Decimal-point character (for printf() / scanf() functions), string
+   conversions, nonmonetary formatting as returned by localeconv
+*/
+#define LC_NUMERIC  _PDCLIB_LC_NUMERIC
+/* Time formats (strftime(), wcsftime()) */
+#define LC_TIME     _PDCLIB_LC_TIME
+/* Messages (not specified but allowed by C99, and specified by POSIX)
+   (used by perror() / strerror())
+*/
+#define LC_MESSAGES _PDCLIB_LC_MESSAGES
+
+/* The category parameter can be any of the LC_* macros to specify if the call
+   to setlocale() shall affect the entire locale or only a portion thereof.
+   The category locale specifies which locale should be switched to, with "C"
+   being the minimal default locale, and "" being the locale-specific native
+   environment. A NULL pointer makes setlocale() return the *current* setting.
+   Otherwise, returns a pointer to a string associated with the specified
+   category for the new locale.
+*/
+char * setlocale( int category, const char * locale );
+
+/* Returns a struct lconv initialized to the values appropriate for the current
+   locale setting.
+*/
+struct lconv * localeconv( void );
+
+CPP_CHECK_END