make: unifdef for other OSes (undefined)

*** 44,68 ****
  #include <mksh/macro.h>         /* SETVAR() */
  #include <mksh/misc.h>          /* enable_interrupt() */
  #include <stdarg.h>             /* va_list, va_start(), va_end() */
  #include <vroot/report.h>       /* SUNPRO_DEPENDENCIES */
  
- #if defined(HP_UX) || defined(linux)
- #include <unistd.h>
- #endif
  
  #ifdef TEAMWARE_MAKE_CMN
  #define MAXJOBS_ADJUST_RFE4694000
  
  #ifdef MAXJOBS_ADJUST_RFE4694000
  extern void job_adjust_fini();
  #endif /* MAXJOBS_ADJUST_RFE4694000 */
  #endif /* TEAMWARE_MAKE_CMN */
  
- #if defined(linux)
- #include <time.h>               /* localtime() */
- #endif
  
  /*
   * Defined macros
   */
  
--- 44,62 ----
*** 721,739 ****
          /* The value of $$ is $ */
          (void) SETVAR(dollar, dollar, false);
          dollar->dollar = false;
  
          /* Set the value of $(SHELL) */
-         #ifdef HP_UX
-         MBSTOWCS(wcs_buffer, NOCATGETS("/bin/posix/sh"));
-         #else
          if (posix) {
            MBSTOWCS(wcs_buffer, NOCATGETS("/usr/xpg4/bin/sh"));
          } else {
            MBSTOWCS(wcs_buffer, NOCATGETS("/bin/sh"));
          }
-         #endif
          (void) SETVAR(shell_name, GETNAME(wcs_buffer, FIND_LENGTH), false);
  
          /*
           * Use " FORCE" to simulate a FRC dependency for :: type
           * targets with no dependencies.
--- 715,729 ----