Merge pull request 'Added build.sh checks for as and ld to be installed' (#427) from build.sh_changes into dev

Reviewed-on: https://git.hush.is/hush/hush3/pulls/427

util/build.sh

@@ -17,6 +17,18 @@ if ! [ -x "$(command -v autoreconf)" ]; then
   exit 1
 fi
 
+if ! [ -x "$(command -v as)" ]; then
+  echo 'Error: as is not installed. Install as and try again.' >&2
+  echo 'On Debian-like systems: apt install binutils' >&2
+  exit 1
+fi
+
+if ! [ -x "$(command -v ld)" ]; then
+  echo 'Error: ld is not installed. Install ld and try again.' >&2
+  echo 'On Debian-like systems: apt install binutils' >&2
+  exit 1
+fi
+
 function cmd_pref() {
     if type -p "$2" > /dev/null; then
         eval "$1=$2"