Recent Commits to freecom:master

patchsize should attempt to patch FreeCom build regardless of compiler that builds tool which may not match compiler that built exe being patched.

dir.c: allow 21.7303 to return NC, ax=0 to mean supported (EDR-DOS)

EDR-DOS returns NC, AX = 0000h from 21.7303. This was incorrectly
detected as "not supported" here. CF unchanged and AL = 00h is
the typical error return, albeit CF unchanged AX unchanged has
also been observed (on dosemu2 + lDOS + SRDISK).

Reference on the correct "unsupported" return:
https://sourceforge.net/p/freedos/mailman/message/59128382/

Incorrect interrupt list entry:
https://fd.lod.bz/rbil/interrup/dos_kernel/217303.html

set CY before calling 21.71 or 21.73 DOS functions (LFN, FAT32)

Between the current lDOS kernel (which doesn't support 21.73),
SRDISK, and dosemu2 revision 6a2f4f527 the return from 21.7303
somehow is with both Carry Flag and AX preserved. This makes the
DIR command think that the call is supported when it isn't.

The proper check is to call with CY set before the call.

increase size of heap from 6KB to 8KB

(size based on discussions on FreeDOS mailing list, TODO validate actual size used and see if can be semi-automated to ensure adjusted up or down as actually required)

loadhigh.c: put maximum array sizes in defines and check for overflow

loadhigh.c: no record UMB region if excluded UMCB is Z and empty

loadhigh_prepare: support lDOS S MCB of type 30h (excluded UMA)

loadhigh_prepare: accept empty MCBs (memory block size zero)

Broke LH on lDOS, reference: https://github.com/FDOS/freecom/issues/166

loadhigh_prepare: on MCB allocation error do not leak memory

fix recursive remove dir

mcb_walk.c: try querying UMB link state even if not on DOS 5+

Current lMS-DOS still reports its version as v4.00 but does fully
support a DOS-managed UMA. As of today lMS-DOS also supports the
SHELLHIGH= directive. Like FreeDOS's this is implemented using
the 21.4B80 extension. Although the internals differ, the outside
observable behaviour is the DOS executable loader allocates both
the environment and the process memory block into the UMA, if
there are free UMBs. However, unlike LH the UMB link state is not
enabled once the control flow is passed to the application. That
means an environment block in a UMB isn't reachable when walking
the MCBs without regard to proceeding past the first UMCB.

The MCB walker is used in FreeCOM's init to validate the
environment block passed to it upon its startup. Reference:
https://github.com/FDOS/freecom/blob/cede733377c454cb93e9038d476582f0d1fcbf0a/shell/init.c#L238

If this check fails, then the shell will prompt for the position
of its executable as follows. This patch makes the MCB walker
enable the UMB link even if the reported DOS version is below 5,
allowing it to find the environment block's UMCB and avoiding
the prompt.

Failed to load the strings resource into memory, the location
pointed to in %COMSPEC% seems to be invalid. Please specify another
location of FreeCOM to try to load the strings from, e.g.:
C:\COMMAND.COM
or just hit enter to cancel to load the strings.

ico files are binary, don't convert linefeeds