makefiles: replace character class with plain char

[kmk3]

When using the "wildcard" internal functions.

This usage has been present since the first "real" commit in the
repository: commit 1379851 ("Baseline firejail 0.9.28").

H_FILE_LIST       = $(sort $(wildcard *.[h]))
C_FILE_LIST       = $(sort $(wildcard *.c))

There is only a single character (i.e.: "h") inside the character class,
so its usage should make no functional difference. It may stem from a
construct that could have originally looked something like this:

C_FILE_LIST       = $(sort $(wildcard *.[ch]))

Which would match both the implementation files and the headers.

From Section 4.4, Using Wildcard Characters in File Names of the
GNU make manual:

A single file name can specify many files using wildcard characters.
The wildcard characters in make are ‘*’, ‘?’ and ‘[…]’, the same as in
the Bourne shell. For example, *.c specifies a list of all the files
(in the working directory) whose names end in ‘.c’.

See also Section 2.13, Pattern Matching Notation of POSIX.1-2017.

Commands used to search, replace and clean up:

$ find . -name .git -prune -o -type f \
  \( -name Makefile -o -name Makefile.in \
  -o -name '*.mk' -o -name '*.mk.in' \) -print0 |
  xargs -0 grep -Fl '$(wildcard *.[h])' | tr '\n' '\000' |
  xargs -0 sed -i.bak -e \
  's/\$(wildcard \*.\[h\])/$(wildcard *.h)/'

$ find . -name .git -prune -o -type f \
  -name '*.bak' -exec rm '{}' +

Note: To make sure that this doesn't actually change anything
functionally, I built firejail-git (AUR) on Artix from master and from
this commit and diffing the resulting files produced no output (other
than showing changes related to the build timestamps).

Misc: Reference to the previous makefile-related changes: commit
2465f92 ("makefiles: make all, clean and distclean PHONY") /
#4024

[kmk3]

By the way, the message is rather verbose because I don't know much make and
this usage has confused me for a while, so I thought that I might as well
document my findings.

[netblue30]

Let's try it out, thanks!