Why would you think that?
pamac uses the git clone command - so there is something else going on.
I just did a make -s in the repo I cloned earlier (I will recheck in moment using pamac build)
build result
[master] $ makepkg -s
==> Making package: proton-ge-custom-bin 1:GE_Proton8_25-1 (ons 29 nov 2023 18:06:27 CET)
==> Checking runtime dependencies...
==> Installing missing dependencies...
[sudo] password for fh:
resolving dependencies...
looking for conflicting packages...
Package (14) New Version Net Change Download Size
multilib/lib32-colord 1.4.6-1 0,38 MiB 0,11 MiB
multilib/lib32-gstreamer 1.22.7-1 3,38 MiB 1,01 MiB
multilib/lib32-gtk3 1:3.24.38-1 10,30 MiB 2,85 MiB
multilib/lib32-lcms2 2.15-1 0,42 MiB 0,16 MiB
multilib/lib32-libepoxy 1.5.10-1 1,09 MiB 0,21 MiB
multilib/lib32-librsvg 2:2.57.0-1 4,41 MiB 1,53 MiB
multilib/lib32-libxkbcommon 1.6.0-1 0,33 MiB 0,13 MiB
multilib/lib32-libxv 1.0.12-1 0,02 MiB 0,01 MiB
multilib/lib32-orc 0.4.34-1 0,72 MiB 0,19 MiB
extra/ffmpeg4.4 4.4.4-3 24,50 MiB 8,65 MiB
multilib/lib32-gst-plugins-base-libs 1.22.7-1 5,44 MiB 1,56 MiB
multilib/lib32-libgudev 238-1 0,04 MiB 0,01 MiB
multilib/lib32-speex 1.2.1-1 0,10 MiB 0,05 MiB
multilib/lib32-vkd3d 1.9-1 1,09 MiB 0,40 MiB
Total Download Size: 16,87 MiB
Total Installed Size: 52,23 MiB
:: Proceed with installation? [Y/n]
:: Retrieving packages...
lib32-gstreamer-1.22.7-1-x86_64 1038,8 KiB 2,36 MiB/s 00:00 [------------------------------------] 100%
lib32-vkd3d-1.9-1-x86_64 410,8 KiB 3,89 MiB/s 00:00 [------------------------------------] 100%
lib32-libepoxy-1.5.10-1-x86_64 217,1 KiB 3,37 MiB/s 00:00 [------------------------------------] 100%
lib32-librsvg-2:2.57.0-1-x86_64 1562,6 KiB 1953 KiB/s 00:01 [------------------------------------] 100%
lib32-orc-0.4.34-1-x86_64 191,7 KiB 2,67 MiB/s 00:00 [------------------------------------] 100%
lib32-lcms2-2.15-1-x86_64 164,6 KiB 2,68 MiB/s 00:00 [------------------------------------] 100%
lib32-gst-plugins-base-libs-1.22... 1592,8 KiB 1695 KiB/s 00:01 [------------------------------------] 100%
lib32-gtk3-1:3.24.38-1-x86_64 2,8 MiB 3,02 MiB/s 00:01 [------------------------------------] 100%
lib32-libxkbcommon-1.6.0-1-x86_64 133,1 KiB 1372 KiB/s 00:00 [------------------------------------] 100%
lib32-colord-1.4.6-1-x86_64 116,6 KiB 2,11 MiB/s 00:00 [------------------------------------] 100%
lib32-speex-1.2.1-1-x86_64 54,3 KiB 1234 KiB/s 00:00 [------------------------------------] 100%
lib32-libgudev-238-1-x86_64 14,1 KiB 157 KiB/s 00:00 [------------------------------------] 100%
lib32-libxv-1.0.12-1-x86_64 9,9 KiB 114 KiB/s 00:00 [------------------------------------] 100%
ffmpeg4.4-4.4.4-3-x86_64 8,6 MiB 6,03 MiB/s 00:01 [------------------------------------] 100%
Total (14/14) 16,9 MiB 11,6 MiB/s 00:01 [------------------------------------] 100%
(14/14) checking keys in keyring [------------------------------------] 100%
(14/14) checking package integrity [------------------------------------] 100%
(14/14) loading package files [------------------------------------] 100%
(14/14) checking for file conflicts [------------------------------------] 100%
(14/14) checking available disk space [------------------------------------] 100%
:: Processing package changes...
( 1/14) installing lib32-vkd3d [------------------------------------] 100%
( 2/14) installing ffmpeg4.4 [------------------------------------] 100%
Optional dependencies for ffmpeg4.4
avisynthplus: AviSynthPlus support
intel-media-sdk: Intel QuickSync support
ladspa: LADSPA filters
nvidia-utils: Nvidia NVDEC/NVENC support
( 3/14) installing lib32-speex [------------------------------------] 100%
( 4/14) installing lib32-lcms2 [------------------------------------] 100%
( 5/14) installing lib32-colord [------------------------------------] 100%
( 6/14) installing lib32-libepoxy [------------------------------------] 100%
( 7/14) installing lib32-librsvg [------------------------------------] 100%
( 8/14) installing lib32-libxkbcommon [------------------------------------] 100%
( 9/14) installing lib32-gtk3 [------------------------------------] 100%
(10/14) installing lib32-gstreamer [------------------------------------] 100%
(11/14) installing lib32-orc [------------------------------------] 100%
(12/14) installing lib32-libxv [------------------------------------] 100%
(13/14) installing lib32-gst-plugins-base-libs [------------------------------------] 100%
(14/14) installing lib32-libgudev [------------------------------------] 100%
:: Running post-transaction hooks...
(1/4) Arming ConditionNeedsUpdate...
(2/4) Refreshing PackageKit...
(3/4) Probing 32-bit GDK-Pixbuf loader modules...
(4/4) Probing 32-bit GTK3 input method modules...
==> Checking buildtime dependencies...
==> Retrieving sources...
-> Downloading GE-Proton8-25_1.tar.gz...
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0
100 408M 100 408M 0 0 13.0M 0 0:00:31 0:00:31 --:--:-- 13.3M
-> Found user_settings.py
-> Found launcher.sh
-> Found pam_limits.conf
==> Validating source files with sha512sums...
GE-Proton8-25_1.tar.gz ... Passed
user_settings.py ... Passed
launcher.sh ... Passed
pam_limits.conf ... Passed
==> Extracting sources...
-> Extracting GE-Proton8-25_1.tar.gz with bsdtar
==> Starting build()...
==> Entering fakeroot environment...
==> Starting package()...
==> Tidying install...
-> Removing libtool files...
-> Purging unwanted files...
-> Removing static library files...
-> Compressing man and info pages...
==> Checking for packaging issues...
==> Creating package "proton-ge-custom-bin"...
-> Generating .PKGINFO file...
-> Generating .BUILDINFO file...
-> Adding changelog file...
-> Adding install file...
-> Generating .MTREE file...
-> Compressing package...
==> Leaving fakeroot environment.
==> Finished making: proton-ge-custom-bin 1:GE_Proton8_25-1 (ons 29 nov 2023 18:07:17 CET)
pamac build proton-ge-custom-bin
pamac build result
$ pamac build proton-ge-custom-bin
Preparing...
Checking proton-ge-custom-bin dependencies...
Resolving dependencies...
Checking inter-conflicts...
To build (1):
proton-ge-custom-bin 1:GE_Proton8_16-1 AUR
Edit build files : [e]
Apply transaction ? [e/y/N] y
Cloning proton-ge-custom-bin build files...
Generating proton-ge-custom-bin information...
==== AUTHENTICATING FOR org.manjaro.pamac.commit ====
Authentication is required to install, update, or remove packages
Authenticating as: FH (fh)
Password:
==== AUTHENTICATION COMPLETE ====
Building proton-ge-custom-bin...
==> Making package: proton-ge-custom-bin 1:GE_Proton8_25-1 (ons 29 nov 2023 18:09:19 CET)
==> Checking runtime dependencies...
==> Checking buildtime dependencies...
==> Retrieving sources...
-> Downloading GE-Proton8-25_1.tar.gz...
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0
100 408M 100 408M 0 0 13.3M 0 0:00:30 0:00:30 --:--:-- 13.3M
-> Found user_settings.py
-> Found launcher.sh
-> Found pam_limits.conf
==> Validating source files with sha512sums...
GE-Proton8-25_1.tar.gz ... Passed
user_settings.py ... Passed
launcher.sh ... Passed
pam_limits.conf ... Passed
==> Removing existing $srcdir/ directory...
==> Extracting sources...
-> Extracting GE-Proton8-25_1.tar.gz with bsdtar
==> Starting build()...
==> Entering fakeroot environment...
==> Starting package()...
==> Tidying install...
-> Removing libtool files...
-> Purging unwanted files...
-> Removing static library files...
-> Compressing man and info pages...
==> Checking for packaging issues...
==> Creating package "proton-ge-custom-bin"...
-> Generating .PKGINFO file...
-> Generating .BUILDINFO file...
-> Adding changelog file...
-> Adding install file...
-> Generating .MTREE file...
-> Compressing package...
==> Leaving fakeroot environment.
==> Finished making: proton-ge-custom-bin 1:GE_Proton8_25-1 (ons 29 nov 2023 18:09:59 CET)
==> Cleaning up...
Checking keyring... [1/1]
Checking integrity... [1/1]
Loading packages files... [1/1]
Checking file conflicts... [1/1]
Checking available disk space... [1/1]
Installing proton-ge-custom-bin (1:GE_Proton8_25-1)... [1/1]
The wine executable used by proton can automatically set the niceness of a process;
Consider adding yourself to the games group to make this work by issuing: usermod -a -G games
Running post-transaction hooks...
Arming ConditionNeedsUpdate... [1/2]
Refreshing PackageKit... [2/2]
Transaction successfully finished.
So thinking - are you by any chance using btrfs ?