mklive: add libgcc to required pkgs; glibc's pthread_cancel needs it :/

mklive.sh.in

@@ -28,7 +28,7 @@
 #-
 trap "error_out $LINENO $?" INT TERM 0
 
-readonly REQUIRED_PKGS="base-files dash coreutils sed tar gawk syslinux grub-x86_64-efi squashfs-tools xorriso"
+readonly REQUIRED_PKGS="base-files libgcc dash coreutils sed tar gawk syslinux grub-x86_64-efi squashfs-tools xorriso"
 readonly INITRAMFS_PKGS="binutils xz device-mapper"
 readonly PROGNAME=$(basename $0)