Add initramfs error message when charging-sdl fails to run

There are devices where charging-sdl/directfb fails (osk-sdl#77).

It's nicer to give an error message than display "Loading..." forever.

aports/main/postmarketos-mkinitfs/APKBUILD

 pkgname=postmarketos-mkinitfs
-pkgver=0.6.7
+pkgver=0.6.8
 pkgrel=0
 pkgdesc="Tool to generate initramfs images for postmarketOS"
 url="https://postmarketos.org"
@@ -24,5 +24,5 @@ package() {
 	mkdir -p "$pkgdir/etc/postmarketos-mkinitfs/hooks/"
 }
 sha512sums="d5abfe9a1298069e6722555c6e16223b09b36af65d879feb64d540aa6cbc009a3aa7f00528bcf656370ec37cc64f925c72ebb77813961cd6ebf22107b57ea029  init.sh.in
-3b029db5eea5f5f2ad486fdcd944340f5c8de04b0d46aaf63c69d181ba87c4d209e3e32d35c9a6f87f214a4303390bd61b5fe980cf533b17d479d42275a6f9ae  init_functions.sh
-e6bf0d326297c7061275156eb9ff354662e740ee5c1ef9e0aab3be80aa50fd32ca5fdaa33a2dfb0431fece3c98c5fea3c40a6f706237aac256b05e92100b8381  mkinitfs.sh"
+4515bc6891110e9c8b1ed8d31a89818c7c222a364bdbdf90097d5d6bbdb97eb889d4dbaec78dc928aa5ff698a8e89a76338e7c63017bf8dfb93f44a293848ca0  init_functions.sh
+f3dc19f6976a95f11ef15155a240574edb46fdaa6885733532abc942c22b43422f9be50b3ae93dc42f9b1a683a62f3246efdb85cd38dbb3abbfdff46bba96617  mkinitfs.sh"

aports/main/postmarketos-mkinitfs/init_functions.sh

@@ -313,7 +313,10 @@ start_charging_mode(){
 		echo "KEY_POWER 1 pgrep -x charging-sdl || charging-sdl -pcf $fontpath"
 	} >/etc/triggerhappy.conf
 	# Start it once and then start triggerhappy
-	charging-sdl -pcf "$fontpath" &
+	(
+		charging-sdl -pcf "$fontpath" \
+			|| show_splash /splash-charging-error.ppm.gz
+	) &
 	thd --deviceglob /dev/input/event* --triggers /etc/triggerhappy.conf
 }
 

aports/main/postmarketos-mkinitfs/mkinitfs.sh

@@ -302,7 +302,8 @@ generate_splash_screens()
 	       "splash-noinitramfsextra" "initramfs-extra not found\\nhttps://postmarketos.org/troubleshooting" "--center" \
 	       "splash-norootfs"         "rootfs not found\\nhttps://postmarketos.org/troubleshooting" "--center" \
 	       "splash-mounterror"       "unable to mount root partition\\nhttps://postmarketos.org/troubleshooting" "--center" \
-	       "splash-debug-shell"      "WARNING\\ndebug-shell is active\\nhttps://postmarketos.org/debug-shell" "--center"
+	       "splash-debug-shell"      "WARNING\\ndebug-shell is active\\nhttps://postmarketos.org/debug-shell" "--center" \
+	       "splash-charging-error"   "CHARGING MODE\\nerror starting charging-sdl\\nhttps://postmarketos.org/troubleshooting" "--center"
 
 	# Ensure cache folder exists
 	mkdir -p "${splash_cache_dir}"