This patch comes from upstream:
https://gitlab.freedesktop.org/farstream/farstream/-/merge_requests/4

From 54987d445ea714b467d901b7daf8c09ed0644189 Mon Sep 17 00:00:00 2001
From: Debarshi Ray <debarshir@freedesktop.org>
Date: Thu, 12 Mar 2020 14:07:23 +0100
Subject: [PATCH] build: Adapt to backwards incompatible change in GNU Make 4.3

GNU Make 4.3 has a backwards incompatible change affecting the use of
number signs or hashes (ie., #) inside function invocations. See:
https://lists.gnu.org/archive/html/info-gnu/2020-01/msg00004.html

In this case, it would expand the '\#' in the '\n\#include \"$(h)\"'
argument to the foreach call to '\#', not '#'. This would lead to
spurious backslashes in front of the '#include' directives in the
generated fs-enumtypes.c file.

Spotted by Ernestas Kulik.
---
 common-modified/gst-glib-gen.mak | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/common-modified/gst-glib-gen.mak b/common-modified/gst-glib-gen.mak
index 14f1ba37..2247a41c 100644
--- a/common-modified/gst-glib-gen.mak
+++ b/common-modified/gst-glib-gen.mak
@@ -6,7 +6,8 @@
 #glib_gen_prefix=gst_color_balance
 #glib_gen_basename=colorbalance
 
-enum_headers=$(foreach h,$(glib_enum_headers),\n\#include \"$(h)\")
+hash:=\#
+enum_headers=$(foreach h,$(glib_enum_headers),\n$(hash)include \"$(h)\")
 
 # these are all the rules generating the relevant files
 $(glib_gen_basename)-enumtypes.h: $(glib_enum_headers)
-- 
GitLab

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<div class='path'>path: <a href='/guix/log/?id=7cd88666d0b76ffca54ade6e2f1e7b62504e8e08&amp;showmsg=1'>root</a>/<a href='/guix/log/gnu?id=7cd88666d0b76ffca54ade6e2f1e7b62504e8e08&amp;showmsg=1'>gnu</a>/<a href='/guix/log/gnu/bootloader?id=7cd88666d0b76ffca54ade6e2f1e7b62504e8e08&amp;showmsg=1'>bootloader</a>/<a href='/guix/log/gnu/bootloader/depthcharge.scm?id=7cd88666d0b76ffca54ade6e2f1e7b62504e8e08&amp;showmsg=1'>depthcharge.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/bootloader/depthcharge.scm?id=7cd88666d0b76ffca54ade6e2f1e7b62504e8e08'>Collapse</a>)</th><th class='left'>Author</th></tr>
<tr class='logheader'><td><span title='2020-05-20 08:30:35 -0400'>2020-05-20</span></td><td class='logsubject'><a href='/guix/commit/gnu/bootloader/depthcharge.scm?id=b460ba7992a0b4af2ddb5927dcf062784539ef7b'>bootloader: grub: Allow booting from a Btrfs subvolume.</a></td><td>Maxim Cournoyer</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* gnu/bootloader/grub.scm (strip-mount-point): Remove procedure.
(normalize-file): Add procedure.
(grub-configuration-file): New BTRFS-SUBVOLUME-FILE-NAME parameter.  When
defined, prepend its value to the kernel and initrd file names, using the
NORMALIZE-FILE procedure.  Adjust the call to EYE-CANDY to pass the
BTRFS-SUBVOLUME-FILE-NAME argument.  Normalize the KEYMAP file as well.
(eye-candy): Add a BTRFS-SUBVOLUME-FILE-NAME parameter, and use it, along with
the NORMALIZE-FILE procedure, to normalize the FONT-FILE and IMAGE nested
variables.  Adjust doc.
* gnu/bootloader/depthcharge.scm (depthcharge-configuration-file): Adapt.
* gnu/bootloader/extlinux.scm (extlinux-configuration-file): Likewise.
* gnu/system/file-systems.scm (btrfs-subvolume?)
(btrfs-store-subvolume-file-name): New procedures.
* gnu/system.scm (operating-system-bootcfg): Specify the Btrfs
subvolume file name the store resides on to the
`operating-system-bootcfg' procedure, using the new
BTRFS-SUBVOLUME-FILE-NAME argument.
* doc/guix.texi (File Systems): Add a Btrfs subsection to document the use of
subvolumes.
* gnu/tests/install.scm (%btrfs-root-on-subvolume-os)
(%btrfs-root-on-subvolume-os-source)
(%btrfs-root-on-subvolume-installation-script)
(%test-btrfs-root-on-subvolume-os): New variables.


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