Support compilers that give a message each time the file being

Support compilers that give a message each time the file being
compiled changes but don't include a file name each error message.
Speed up by searching for regexps one by one instead of combining.
(compile-internal): Takes more optional arguments.  All five regexp
alists can be given as argument.
Change name of variable regexp-alist to error-regexp-alist. Change
some local variables directly by setq instead of rebinding by let.
(compilation-shell-minor-mode): New minor mode.
Similar to compilation-minor-mode, but key bindings don't
collide with shell mode.
(compilation-shell-minor-mode-map, compilation-shell-minor-mode):
New variables.
(compile-auto-highlight): Doc fix.
(compilation-error-regexp-alist): Removed unnecessary line break
in first regexp.  Replaced \\(\\|.* on \\) by \\(.* on \\)? in
regexp for Absoft FORTRAN 77 Compiler 3.1.3.  Added regexp for
SPARCcompiler Pascal.  Divided long line in regexp for Cray C
compiler error messages.  Made comment fit in line at regexp for
Sun Ada (VADS, Solaris).  FILE-IDX may be nil, meaning an
error message with no file name, so the file name must be taken
from an earlier message.  LINE-IDX may be a function which is
called with two arguments the file name and column strings and
returns an error position descriptor.
(compilation-enter-directory-regexp-alist)
(compilation-leave-directory-regexp-alist): New variables.
(compilation-file-regexp-alist)
(compilation-nomessage-regexp-alist): New variables.
(grep-regexp-alist): Removed unnecessary ^ at beginning of regexp.
(compilation-enter-directory-regexp)
(compilation-leave-directory-regexp): Variables deleted.
Replaced by compilation-enter-directory-regexp-alist and
compilation-leave-directory-regexp-alist.
(compilation-buffer-p): Return true also for buffer in
compilation-shell-minor-mode.
(compilation-next-error-locus): Split a long line.
(count-regexp-groupings): Comment about this function not being
needed any more.
(compilation-current-file, compilation-regexps); New variables.
(compilation-parse-errors): Large parts rewritten.  Don't put the
regexps together in one large regexp, instead match them one by one.
Support the generalized subexpression indices.
(compile-collect-regexps, compile-buffer-substring): New functions
supporting compilation-parse-errors.