guix: build for Linux HOSTS with `-static-libgcc`

[kevkevinpal]

mentioned in: bitcoin#33181

"Concept ACK f06c6e1

The build uses a lot more space 49,4 GIB ( 51 GiB (freespace before run - 1.6 GiB freespace after run) (will post proof later, have to run)

Good followup would be to adjust the guix build gate accordantly.
(will do some extra research on this to rule out something has changed on my guix vm) " - janb84

[djkazic]

Hi! 👋🏻 I got my guix build env setup. I then did a Linux build for x86_64.

These were the disk space stats.

Before:

$ df -h /gnu/store                   
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda5       512G   84G  407G  17% /gnu/store

After:

$ df -BG /gnu/store
Filesystem     1G-blocks  Used Available Use% Mounted on
/dev/sda5           512G   88G      403G  18% /gnu/store

$ du -h --max-depth 1 guix-build-c66e98875439/
803M	guix-build-c66e98875439/output
3.8G	guix-build-c66e98875439/distsrc-c66e98875439-x86_64-linux-gnu
12K	guix-build-c66e98875439/var
4.6G	guix-build-c66e98875439/

---

Next, I ran HOSTS="x86_64-w64-mingw32" ./contrib/guix/guix-build

After (+10 GiB):

Filesystem     1G-blocks  Used Available Use% Mounted on
/dev/sda5           512G   98G      393G  20% /gnu/store

These numbers makes this change seem reasonable (1.5x safety factor):

-        *mingw*)  required_KiB=7600000 ;;
+        *mingw*)  required_KiB=15728640 ;;

---

Then I ran HOSTS="aarch64-linux-gnu" ./contrib/guix/guix-build.

After (+6 GiB):

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda5       512G  104G  387G  22% /gnu/store

---

Then I setup the SDK for macOS. This established a new before snapshot of disk use:

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda5       512G  116G  375G  24% /gnu/store

Then I ran HOSTS="x86_64-apple-darwin" ./contrib/guix/guix-build.

After (+5 GiB):

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda5       512G  121G  370G  25% /gnu/store

That's grounds for updating this (5 GiB * 1.5x safety factor):

-        *darwin*) required_KiB=440000 ;;
+        *darwin*) required_KiB=8388608 ;;

[djkazic]

If everything above looks good, I can raise a PR with this as the patch:

for host in $HOSTS; do
    case "$host" in
-        *darwin*) required_KiB=440000 ;;
-        *mingw*)  required_KiB=7600000 ;;
-        *)        required_KiB=6400000 ;;
+        *darwin*) required_KiB=8388608 ;;   # 8 GiB (5 GiB measured * 1.5, rounded)
+        *mingw*)  required_KiB=15728640 ;;  # 15 GiB (10 GiB measured * 1.5)
+        *)        required_KiB=6400000 ;;   # ~6.1 GiB, matches aarch64 measurement (~6 GiB)
    esac
    total_required_KiB=$((total_required_KiB+required_KiB))
done