README: add Open Watcom as a tested compiler

Tested sfeed, sfeed_plain and sfeed_html for now.

There are minor changes required for sfeed and some additional compatibility
function changes required to make the format tools compile.

Rough list of changes required:
- xml.c: rename getchar_unlocked -> getchar
- sfeed.c: EOVERFLOW -> ENOMEM
- wcwidth: just filter ASCII range < 32 = -1 and > 127 = 0, rest = 1.
- getline
- localtime_r -> just do a localtime + memcpy.

Make sure to increase stack size when compiling:

	owcc -k32768 -Os -s -o sfeed.exe sfeed.c util.c xml.c

Resulting .exe binary is 27KB, 17KB compressed with UPX.

The HTML output looks fine in Netscape Navigator and Internet Explorer 3 :)

1 files changed, 1 insertions, 1 deletions

diff --git a/README b/README
index dcff323..35ecd75 100644
--- a/README
+++ b/README
@@ -165,7 +165,7 @@ OS tested
 - Windows (cygwin gcc + mintty, mingw).
 - HaikuOS
 - SerenityOS
-- FreeDOS (djgpp).
+- FreeDOS (djgpp, Open Watcom).
 - FUZIX (sdcc -mz80, with the sfeed parser program).