Rename generated version header to avoid conflict on case insensitive filesystems

[DDRBoxman]

On macOS the compiler was not correctly choosing between the Version.h header from MPD or the version.h header in mpdclient.

[MaxKellermann]

How can there be a conflict? These are in different directories, and libmpdclient's version.h isn't even in the search path - it's below "mpd/".

[DDRBoxman]

This is the error I'm seeing after the updates to master this morning

In file included from ../../src/db/plugins/ProxyDatabasePlugin.cxx:31:
../../subprojects/libmpdclient/include/mpd/client.h:84:10: warning: non-portable path to file '"Version.h"'; specified path differs in case from file name on disk [-Wnonportable-include-path]
#include "version.h"
         ^~~~~~~~~~~
         "Version.h"
../../src/db/plugins/ProxyDatabasePlugin.cxx:169:5: error: function-like macro 'LIBMPDCLIENT_CHECK_VERSION' is not defined
#if LIBMPDCLIENT_CHECK_VERSION(2,17,0)
    ^
../../src/db/plugins/ProxyDatabasePlugin.cxx:176:5: error: function-like macro 'LIBMPDCLIENT_CHECK_VERSION' is not defined
#if LIBMPDCLIENT_CHECK_VERSION(2,20,0)
    ^
../../src/db/plugins/ProxyDatabasePlugin.cxx:183:5: error: function-like macro 'LIBMPDCLIENT_CHECK_VERSION' is not defined
#if LIBMPDCLIENT_CHECK_VERSION(2,21,0)
    ^
../../src/db/plugins/ProxyDatabasePlugin.cxx:212:5: error: function-like macro 'LIBMPDCLIENT_CHECK_VERSION' is not defined
#if LIBMPDCLIENT_CHECK_VERSION(2,21,0)
    ^
../../src/db/plugins/ProxyDatabasePlugin.cxx:336:5: error: function-like macro 'LIBMPDCLIENT_CHECK_VERSION' is not defined
#if LIBMPDCLIENT_CHECK_VERSION(2,21,0)
    ^
../../src/db/plugins/ProxyDatabasePlugin.cxx:823:5: error: function-like macro 'LIBMPDCLIENT_CHECK_VERSION' is not defined
#if LIBMPDCLIENT_CHECK_VERSION(2,21,0)
    ^
1 warning and 6 errors generated.

[MaxKellermann]

Okay, I see, that's because libmpdclient is not installed, so version.h is not in the same directory as client.h, and your compiler flags happen to be in this order. But there must be a better way to fix this; your solution is too fragile, it just makes the symptom go away, but doesn't really solve the general problem.
This is the bad commit in libmpdclient, me trying to solve a subproject problem but not properly: MusicPlayerDaemon/libmpdclient@d8b10bb63

[MaxKellermann]

I implemented a better solution which avoids the conflict completely instead of sidestepping it with a different filename.

[DDRBoxman]

Hmm, just checked out master and I'm still running into the import conflict 🤔

[MaxKellermann]

Is there a version.h leftover from the previous build? Did you rebuild from scratch?

[DDRBoxman]

I deleted the output folder and ran from scratch, yeah.

Updated to the latest master again and now it seems that id3 is mad too

In file included from ../../src/tag/FixString.cxx:4:
In file included from ../../src/tag/FixString.hxx:7:
In file included from /Users/ddrboxman/Library/Android/sdk/ndk/26.1.10909125/toolchains/llvm/prebuilt/darwin-x86_64/bin/../sysroot/usr/include/c++/v1/string_view:205:
In file included from /Users/ddrboxman/Library/Android/sdk/ndk/26.1.10909125/toolchains/llvm/prebuilt/darwin-x86_64/bin/../sysroot/usr/include/c++/v1/__algorithm/min.h:13:
In file included from /Users/ddrboxman/Library/Android/sdk/ndk/26.1.10909125/toolchains/llvm/prebuilt/darwin-x86_64/bin/../sysroot/usr/include/c++/v1/__algorithm/comp_ref_type.h:13:
In file included from /Users/ddrboxman/Library/Android/sdk/ndk/26.1.10909125/toolchains/llvm/prebuilt/darwin-x86_64/bin/../sysroot/usr/include/c++/v1/__debug:16:
In file included from /Users/ddrboxman/Library/Android/sdk/ndk/26.1.10909125/toolchains/llvm/prebuilt/darwin-x86_64/bin/../sysroot/usr/include/c++/v1/cstddef:41:
../../subprojects/libid3tag-0.15.1b/version:1:1: error: expected unqualified-id
0.15.1b
^

[DDRBoxman]

Ah, yeah definitely the same include path leaking issue there too

[DDRBoxman]

libid3tag_dep = declare_dependency(
  link_with: libid3tag,
  include_directories: include_directories('.'),
)

Going to try to be more explicit with that include_directories export and see if that fixes the id3 issue

[DDRBoxman]

Not sure where the i3dtag wrap file comes from but this does the trick, and lets me build the whole project.

fs = import('fs')

project(
  'libid3tag', 'c',
  version: '0.15.1b',
  license: 'GPLv2+',
)

compiler = meson.get_compiler('c')

conf = configuration_data()
conf.set('HAVE_ASSERT_H', true)
conf.set('HAVE_FTRUNCATE', compiler.has_function('ftruncate'))
conf.set('HAVE_INTTYPES_H', true)
conf.set('HAVE_LIBZ', false) # TODO
conf.set('HAVE_STDINT_H', true)
conf.set('HAVE_STDIO_H', true)
conf.set('HAVE_STDLIB_H', true)
conf.set('HAVE_STRINGS_H', true)
conf.set('HAVE_STRING_H', true)
conf.set('HAVE_SYS_STAT_H', compiler.has_header('sys/stat.h'))
conf.set('HAVE_SYS_TYPES_H', true)
conf.set('HAVE_UNISTD_H', compiler.has_header('unistd.h'))
configure_file(output: 'config.h', configuration: conf)

add_project_arguments('-DHAVE_CONFIG_H', language: 'c')

libid3tag = static_library(
  'id3tag',
  'version.c', 'ucs4.c', 'latin1.c', 'utf16.c', 'utf8.c',
  'parse.c', 'render.c', 'field.c', 'frametype.c', 'compat.c',
  'genre.c', 'frame.c', 'crc.c', 'util.c', 'tag.c', 'file.c',
)

copy = fs.copyfile('id3tag.h', 'include/id3tag.h')

libid3tag_dep = declare_dependency(
  link_with: libid3tag,
  dependencies: [copy]
  include_directories: include_directories('include'),
)