Fix compile on Alpine Linux when using fortified headers

This commit removes obsolete compatibility code that was causing
compilation errors on Alpine Linux when the fortify-headers package is
installed. In short, the readlink, symlink and realpath compatibility
functions in src/lib/libast/comp don't work with Alpine Linux's
fortified headers. None of these functions are necessary to compile on
current operating systems (tested on Linux with glibc and musl,
{Free,Net,Open,DragonFly}BSD, illumos, Haiku and Cygwin) so these can be
safely deleted. Additionally, some spurious macro hackery relating to
strlcpy, strlcat and networking functions used in libcmd uname has also
been deleted. (The patch to univlib.h is taken from
ksh93#743 (comment).)

Co-authored-by: xorrvin <[email protected]>

src/cmd/ksh93/features/poll

@@ -123,23 +123,13 @@ tst socketpair_shutdown_mode note{ fchmod() after socketpair() shutdown() }end e
  }
 }end
 cat{
- #if _lib_poll
- # define poll _SYS_poll
- #else
- # undef _hdr_poll
- # undef _sys_poll
- #endif /* _lib_poll */
  #if _hdr_poll
  # include <poll.h>
  #else
  # if _sys_poll
  # include <sys/poll.h>
  # endif /* _sys_poll */
  #endif /* _hdr_poll */
- #if _lib_poll
- # undef poll
- extern int poll(struct pollfd*,unsigned long,int);
- #endif /* _lib_poll */
  #if _lib_select
  # ifndef FD_ZERO
  # define FD_ZERO(x) (*(x)=0)

src/lib/libast/Mamfile

@@ -2746,24 +2746,6 @@ make install virtual
  exec - compile ${<}
  done
 
- make readlink.o
- make comp/readlink.c
- prev include/error.h
- prev comp/fakelink.h implicit
- prev include/ast.h
- done
- exec - compile ${<}
- done
-
- make symlink.o
- make comp/symlink.c
- prev include/error.h
- prev comp/fakelink.h
- prev include/ast.h
- done
- exec - compile ${<}
- done
-
  make getpgrp.o
  make comp/getpgrp.c
  prev include/ast_std.h
@@ -3103,14 +3085,6 @@ make install virtual
  exec - compile ${<}
  done
 
- make realpath.o
- make comp/realpath.c
- prev ast_map.h
- prev include/ast.h
- done
- exec - compile ${<}
- done
-
  make regcmp.o
  make comp/regcmp.c
  prev align.h

src/lib/libast/features/map.c

@@ -231,9 +231,6 @@ main(void)
  printf("#define re_comp _ast_re_comp\n");
  printf("#undef re_exec\n");
  printf("#define re_exec _ast_re_exec\n");
- printf("#undef realpath\n");
- printf("#define realpath _ast_realpath\n");
- printf("extern char* realpath(const char*, char*);\n");
 #endif
  /* Override the native regex library in favor of libast's regex functions */
  printf("#undef regaddclass\n");

src/lib/libast/misc/univlib.h

@@ -33,9 +33,7 @@
 #define _UNIVLIB_H
 
 #define getuniverse ______getuniverse
-#define readlink ______readlink
 #define setuniverse ______setuniverse
-#define symlink ______symlink
 #define universe ______universe
 
 #include <ast.h>
@@ -49,9 +47,7 @@
 #endif
 
 #undef getuniverse
-#undef readlink
 #undef setuniverse
-#undef symlink
 #undef universe
 
 #if _cmd_universe
@@ -73,9 +69,7 @@ extern char univ_env[];
 #endif
 
 extern int getuniverse(char*);
-extern int readlink(const char*, char*, int);
 extern int setuniverse(int);
-extern int symlink(const char*, const char*);
 extern int universe(int);
 
 #endif

src/lib/libast/string/strlcat.c

@@ -20,12 +20,8 @@
  * strlcat implementation
  */
 
-#define strlcat ______strlcat
-
 #include <ast.h>
 
-#undef strlcat
-
 #undef _def_map_ast
 #include <ast_map.h>
 

src/lib/libast/string/strlcpy.c

@@ -20,12 +20,8 @@
  * strlcpy implementation
  */
 
-#define strlcpy ______strlcpy
-
 #include <ast.h>
 
-#undef strlcpy
-
 #undef _def_map_ast
 #include <ast_map.h>
 

src/lib/libcmd/uname.c

@@ -66,11 +66,6 @@ static const char usage[] =
 " \bsysconf\b(3), \bsysinfo\b(2)]"
 ;
 
-#define getdomainname ______getdomainname
-#define gethostid ______gethostid
-#define gethostname ______gethostname
-#define sethostname ______sethostname
-
 #include <cmd.h>
 #include <ctype.h>
 #include <stdio.h>
@@ -84,24 +79,6 @@ static const char usage[] =
 # include <sys/utsname.h>
 #endif
 
-#undef getdomainname
-#undef gethostid
-#undef gethostname
-#undef sethostname
-
-#if _lib_getdomainname
-extern int getdomainname(char*, size_t);
-#endif
-#if _lib_gethostid
-extern long gethostid(void);
-#endif
-#if _lib_gethostname
-extern int gethostname(char*, size_t);
-#endif
-#if _lib_sethostname
-extern int sethostname(const char*, size_t);
-#endif
-
 #ifndef HOSTTYPE
 #define HOSTTYPE "unknown"
 #endif