Squashed 'xdgmime-source/' changes from 28b70c4..3e7ee2d

Squashed 'xdgmime-source/' changes from 28b70c4..3e7ee2d

3e7ee2d Add SPDX-License-Identifier tags in source files
d385402 src/: LGPLv2+ -> LGPLv2.1+
0122cb5 xdgmime: Finer handling for cases where mmap() is not available
c501188 xdgmime: Prevent infinite loops from badly-formed MIME registrations
462198f xdgmime: Add xdg_mime_set_dirs() method to override XDG envvars
1414820 Add missing S_ISREG definitions for VS2022
ecbc52c xdgmimemagic: Add an assertion to clarify state after hitting an error
95e3187 test-mime-data: output errors to stderr
fe2f298 ci: Test meson build
ade1de1 build: Add meson support
0722d76 ci: Fix shared-mime-info test not exercising our build
92f6a09 xdgmimemagic: Fix unused variable warning when !LITTLE_ENDIAN
50a624b Fix segfaults due to strict ISO C99 mode enforcement
7cc63be Makefile: Add support for POSIX make
d64963b test-mime-data: fail when an error occurs
1c521ab add OOM handling in mimemagic
1318486 Silence an uninitialize variable warning
3ae3ed6 xdgmime: Call xdg_mime_init() before xdg_mime_list_mime_parents()

git-subtree-dir: xdgmime-source
git-subtree-split: 3e7ee2dc8edde524858ad9a109dabe26980cf2e5