Fix crash on long PS1 prompt (Solaris patch 195-17824699)

Original report and info:
https://www.mail-archive.com/ast-developers@lists.research.att.com/msg01677.html
https://www.mail-archive.com/ast-developers@lists.research.att.com/msg01679.html

Patch pulled in from:
https://raw.githubusercontent.com/oracle/solaris-userland/master/components/ksh93/patches/195-17824699.patch

src/cmd/ksh93/edit/edit.c: ed_setup():
- Prevent the ed_setup() function from writing past ep->e_prompt,
  which is set to the local char prompt[PRSIZE] variable in
  ed_emacsread().

src/cmd/ksh93/include/edit.h:
- Increase maximum prompt size, PRSIZE, to 256.

NEWS

@@ -3,6 +3,11 @@ For full details, see the git log at: https://github.com/ksh93/ksh
 
 Any uppercase BUG_* names are modernish shell bug IDs.
 
+2021-01-08:
+
+- Fixed a crash on exceeding the maximum size of the $PS1 prompt.
+  The maximum size is also increased from 160 to 256 bytes.
+
 2021-01-07:
 
 - Fixed a crash that could occur while ksh updated ${.sh.match}.

src/cmd/ksh93/edit/edit.c

@@ -658,7 +658,8 @@ void	ed_setup(register Edit_t *ep, int fd, int reedit)
 			{
 				int skip=0;
 				ep->e_crlf = 0;
-				*pp++ = c;
+				if(pp<ppmax)
+					*pp++ = c;
 				for(n=1; c = *last++; n++)
 				{
 					if(pp < ppmax)

src/cmd/ksh93/include/edit.h

@@ -59,7 +59,7 @@
 #endif /* SHOPT_MULTIBYTE */
 
 #define TABSIZE	8
-#define PRSIZE	160
+#define PRSIZE	256
 #define MAXLINE	1024		/* longest edit line permitted */
 
 typedef struct _edit_pos

src/cmd/ksh93/include/version.h

@@ -20,7 +20,7 @@
 
 #define SH_RELEASE_FORK	"93u+m"		/* only change if you develop a new ksh93 fork */
 #define SH_RELEASE_SVER	"1.0.0-alpha"	/* semantic version number: https://semver.org */
-#define SH_RELEASE_DATE	"2021-01-07"	/* must be in this format for $((.sh.version)) */
+#define SH_RELEASE_DATE	"2021-01-08"	/* must be in this format for $((.sh.version)) */
 
 /* Scripts sometimes field-split ${.sh.version}, so don't change amount of whitespace. */
 /* Arithmetic $((.sh.version)) uses the last 10 chars, so the date must be at the end. */