Fix 'print -s -f'

This fix is backported from the Vashisht/Rader ksh2020 branch.

src/cmd/ksh93/bltins/print.c:
- Fix syncing history when print -s -f is used. For example, the
  following now correctly adds a 'cd' command to the history:
	print -s -f 'cd -- %q\n' "$PWD"
  Ref.:	https://github.com/att/ast/issues/425
	https://github.com/att/ast/pull/442

src/cmd/ksh93/include/version.h:
- Version date bump.

(cherry picked from commit 46ba7ecdc5c14cd73f6cb24b16c50bdc331a000e)

NEWS

@@ -4,6 +4,14 @@ For full details, see the git log at:
 
 Any uppercase BUG_* names are modernish shell bug IDs.
 
+2020-05-14:
+
+- Fix syncing history when print -s -f is used. For example, the
+  following now correctly adds a 'cd' command to the history:
+	print -s -f 'cd -- %q\n' "$PWD"
+  Ref.:	https://github.com/att/ast/issues/425
+	https://github.com/att/ast/pull/442
+
 2020-05-13:
 
 - Fix BUG_CASELIT: an undocumented 'case' pattern matching misbehaviour that

src/cmd/ksh93/bltins/print.c

@@ -329,7 +329,13 @@ skip2:
 		} while(*pdata.nextarg && pdata.nextarg!=argv);
 		if(pdata.nextarg == nullarg && pdata.argsize>0)
 			sfwrite(outfile,stakptr(staktell()),pdata.argsize);
-		if(sffileno(outfile)!=sffileno(sfstderr))
+		/*
+		 * -f flag skips adding newline at the end of output, which causes issues
+		 * with syncing history if -s and -f are used together. So don't sync now
+		 * if sflag was given. History is synced later with hist_flush() function.
+		 * https://github.com/att/ast/issues/425
+		 */
+		if(!sflag && sffileno(outfile)!=sffileno(sfstderr))
 			sfsync(outfile);
 		sfpool(sfstderr,pool,SF_WRITE);
 		exitval = pdata.err;

src/cmd/ksh93/include/version.h

@@ -17,4 +17,4 @@
 *                  David Korn <dgk@research.att.com>                   *
 *                                                                      *
 ***********************************************************************/
-#define SH_RELEASE	"93u+m 2020-05-13"
+#define SH_RELEASE	"93u+m 2020-05-14"