I solved the problem by changing the line like this. I am not sure if it is correct

meson --buildtype=release . build --prefix=/usr -Dwith_docs=false

picom 11

  Subprojects
    test.h   : YES

  User defined options
    buildtype: release
    prefix   : /usr
    with_docs: true

Found ninja-1.12.1 at /usr/bin/ninja
WARNING: Running the setup command as `meson [options]` instead of `meson setup [options]` is ambiguous and deprecated.
ninja: Entering directory `build'
[28/35] Generating man/picom-trans.1 with a custom command
FAILED: man/picom-trans.1 
/usr/bin/a2x -a picom-version=vgit-df4c6 --format manpage ../man/picom-trans.1.asciidoc -D /home/friday13/.cache/yay/picom-ftlabs-git/src/picom/build/man
a2x: ERROR: "xmllint" --nonet --noout --valid "/home/friday13/.cache/yay/picom-ftlabs-git/src/picom/build/man/picom-trans.1.xml" ret

Sure thing, feel free to do so, although I can't guarantee to be the quickest one to notice changes.

Thanks @nx-que,

after modifying your changes slightly, I am happy with the current state of the package. Let me know if anything else needs solving. Please also notify me when the patch is no longer needed so that I can remove it. I no longer use X11 and therefore am not keeping up to date with this fork - i am merely the maintainer. I can add you as a 2nd maintainer if you wish?

:)

Requires libepoxy to build and run, I would also recommend including the patch below as the current master has EWMH fullscreen border broken for a while now (fixed in yshui version).
Patch for changes mentioned

diff --git a/.SRCINFO b/.SRCINFO
index aacaee7..e2aba1f 100644
--- a/.SRCINFO
+++ b/.SRCINFO
@@ -19,6 +19,7 @@ pkgbase = picom-ftlabs-git
    depends = libx11
    depends = xcb-util-renderutil
    depends = libxcb
+   depends = libepoxy
    depends = xcb-util-image
    depends = libxext
    depends = pixman
@@ -37,6 +38,8 @@ pkgbase = picom-ftlabs-git
    conflicts = picom
    replaces = compton-git
    source = git+https://github.com/FT-Labs/picom.git#branch=next
+   source = fix_ewmh_fullscreen.patch
    md5sums = SKIP
+   md5sums = fddbe446beffe6f05517824083da4724

 pkgname = picom-ftlabs-git
diff --git a/PKGBUILD b/PKGBUILD
index 4e7c996..6822b31 100644
--- a/PKGBUILD
+++ b/PKGBUILD
@@ -11,7 +11,7 @@ pkgdesc="picom fork by FT-Labs including animations (git-version)"
 arch=(i686 x86_64)
 url="https://github.com/FT-Labs/${_gitname}"
 license=('MIT' 'MPL2')
-depends=('libgl' 'libev' 'pcre2' 'libx11' 'xcb-util-renderutil' 'libxcb' 'xcb-util-image' 'libxext'
+depends=('libgl' 'libev' 'pcre2' 'libx11' 'xcb-util-renderutil' 'libxcb' 'libepoxy' 'xcb-util-image' 'libxext'
          'pixman' 'libconfig' 'libdbus' 'hicolor-icon-theme')
 makedepends=('git' 'mesa' 'meson' 'asciidoc' 'uthash' 'xorgproto')
 optdepends=('dbus:          To control picom via D-Bus'
@@ -21,8 +21,14 @@ optdepends=('dbus:          To control picom via D-Bus'
 provides=('compton' 'compton-git' 'picom')
 conflicts=('compton' 'compton-git' 'picom')
 replaces=('compton-git')
-source=(git+"https://github.com/FT-Labs/${_gitname}.git#branch=next")
-md5sums=("SKIP")
+source=(
+  git+"https://github.com/FT-Labs/${_gitname}.git#branch=next"
+  "fix_ewmh_fullscreen.patch"
+)
+md5sums=(
+  "SKIP"
+  "fddbe446beffe6f05517824083da4724"
+)

 pkgver() {
     cd ${_gitname}
@@ -31,6 +37,11 @@ pkgver() {
     printf "%s_%s\n" "${_commits}" "${_date}" | sed 's/-/./g'
 }

+prepare() {
+  cd "${srcdir}/${_gitname}"
+  patch -d src -p1 < "${srcdir}/fix_ewmh_fullscreen.patch"
+}
+
 build() {
   cd "${srcdir}/${_gitname}"
   meson --buildtype=release . build --prefix=/usr -Dwith_docs=true
diff --git a/fix_ewmh_fullscreen.patch b/fix_ewmh_fullscreen.patch
new file mode 100644
index 0000000..a214e8d
--- /dev/null
+++ b/fix_ewmh_fullscreen.patch
@@ -0,0 +1,13 @@
+--- a/win.c
++++ b/win.c
+@@ -1303,10 +1303,6 @@
+ bool win_update_prop_fullscreen(struct x_connection *c, const struct atom *atoms,
+                                 struct managed_win *w) {
+   auto prop = x_get_prop(c, w->client_win, atoms->a_NET_WM_STATE, 12, XCB_ATOM_ATOM, 0);
+-  if (!prop.nitems) {
+-      return false;
+-  }
+-
+   bool is_fullscreen = false;
+   for (uint32_t i = 0; i < prop.nitems; i++) {
+       if (prop.atom[i] == atoms->a_NET_WM_STATE_FULLSCREEN) {

thank's @fazzi i will check.. But seems rebuilding solved the issue already. Still on X11 with i3 ;)

Hey @killajoe. I am afraid I no longer use X11 and am therefore unable to test for you.

Try making an issue on the github page. I am not a maintainer of the picom fork, I just packaged it on the AUR.

@MarsSeed, the package seems to build fine with a valid version number for me in a clean chroot.

I have implemented your change on the pcre2.

hmm for me it coredumps under nvidia:

Dez 17 12:07:29 SLIMSHADY64 systemd-coredump[81857]: [🡕] Process 1512 (picom) of user 1000 dumped core.

                                                     Stack trace of thread 1512:
                                                     #0  0x000056220f145fd1 n/a (picom + 0x3dfd1)
                                                     #1  0x000056220f14a335 n/a (picom + 0x42335)
                                                     #2  0x000056220f11af26 n/a (picom + 0x12f26)
                                                     #3  0x000056220f11c3cc n/a (picom + 0x143cc)
                                                     #4  0x00007fd7741ea0cb ev_invoke_pending (libev.so.4 + 0x50cb)
                                                     #5  0x00007fd7741edd10 ev_run (libev.so.4 + 0x8d10)
                                                     #6  0x000056220f115b0f n/a (picom + 0xdb0f)
                                                     #7  0x00007fd773bd4cd0 n/a (libc.so.6 + 0x27cd0)
                                                     #8  0x00007fd773bd4d8a __libc_start_main (libc.so.6 + 0x27d8a)
                                                     #9  0x000056220f116fa5 n/a (picom + 0xefa5)
                                                     ELF object binary architecture: AMD x86-64