Add Log message giving source for Boot, System & Font Merges.
Utilise recent Install_Log command to log the source directory for a Merge. If command does not exist, it does not give error.
During testing of the above change, an unrelated bug in the !Font merge process was found that can cause it to put merged fonts in totally the wrong place.
The Config2PluginxxxxMerge.c.Main function static_ReadVariables(), if APP=FONTMERGE, uses the value of Font$Path to set Destination (the merge target) from the third path element from the end, which assumes it is the system !Fonts.
However, if a *FontInstall mydirectory. was done before the *FontInstall in
!Fonts.!Boot, then Font$Path will be set to 4 elements, eg:
ADFS::SSD.$.!BOOT.Resources.!Fonts.,mydirectory.,<Font$Prefix>.,Resources:$.Fonts.
so any new fonts wrongly go into mydirectory.
The fix now finds the first directory seen which ends in ".!Fonts.", which is the LAST match in the path string. This is better, though not totally foolproof.