🚀 go-pugleaf

The following patch allocates storage on the stack in the DIRONLY
macro, rather than using the savestring function().  The macro is
a tiny bit uglier, but it doesn't waste memory.

Performance should not suffer since good compilers will recognize that
"(p - (s))" is a common subexpression.

diff -c make/commands.c:1.1.1.1 make/commands.c:1.3
*** make/commands.c:1.1.1.1	Mon Nov 16 15:12:56 1992
--- make/commands.c	Mon Nov 16 15:12:56 1992
***************
*** 65,71 ****
  #define	LASTSLASH(s)	rindex ((s), '/')
  #define	FILEONLY(s)	(p != 0 ? p + 1 : (s))
  #define	DIRONLY(s)	(p == 0 ? "./" : p == (s) ? "/" \
! 			 : savestring ((s), (p - (s)) + 1))
  
    /* $* is the stem from an implicit or static pattern rule.  */
    if (file->stem == 0)
--- 65,71 ----
  #define	LASTSLASH(s)	rindex ((s), '/')
  #define	FILEONLY(s)	(p != 0 ? p + 1 : (s))
  #define	DIRONLY(s)	(p == 0 ? "./" : p == (s) ? "/" \
! 			 : strncpy(alloca((p - (s)) + 1), s, (p - (s))))
  
    /* $* is the stem from an implicit or static pattern rule.  */
    if (file->stem == 0)