Use openssl sha to calculate shasums [EFForg#1504]

ErinCall · ErinCall · commit 63fb65695494 · 2015-06-11T13:14:13.000-07:00
sha256sum is not available on BSD systems. There's a shasum that may be
available everywhere, but openssl should be even more ubiquitous.

openssl's output looks a little different from the sha*sums' commands,
but I don't think that matters much. For posterity, sha256sum looks like

a54680cfaa331e1d1d6e2f61b2fa5aafe89302046ebc92d98f0070a63459e821  pkg/https-everywhere-5.0.4~578663d-amo.xpi

while openssl sha looks like

SHA256(pkg/https-everywhere-5.0.4~578663d-amo.xpi)= a54680cfaa331e1d1d6e2f61b2fa5aafe89302046ebc92d98f0070a63459e821
diff --git a/locate-gnu-utils.sh b/locate-gnu-utils.sh
@@ -18,13 +18,6 @@ if [ -x "$GMKTEMP" ]; then
 fi
 unset GMKTEMP
 
-SHA256SUM=$(which sha256sum 2>/dev/null || true)
-GSHA256SUM=$(which gsha256sum 2>/dev/null || true)
-if [ -x "$GSHA256SUM" ]; then
-  SHA256SUM="$GSHA256SUM"
-fi
-unset GSHA256SUM
-
 check_for_gnu_version() {
   gnu_available=$("$1" --version 2>&1 | grep GNU)
   if [ ! "$gnu_available" ]; then
@@ -38,4 +31,3 @@ check_for_gnu_version() {
 
 check_for_gnu_version "$MKTEMP" "mktemp"
 check_for_gnu_version "$READLINK" "readlink"
-check_for_gnu_version "$SHA256SUM" "sha256sum"
diff --git a/test.sh b/test.sh
@@ -67,5 +67,5 @@ bash test-ruleset-coverage.sh
 echo "To reproduce this build (https://wiki.debian.org/ReproducibleBuilds)," \
      "please use this version of sqlite3:"
 sqlite3 -version
-shasum=$("$SHA256SUM" "$XPI_NAME")
-echo -e "Git commit `git rev-parse HEAD`\nsha256sum  $shasum"
+shasum=$(openssl sha -sha256 "$XPI_NAME")
+echo -e "Git commit `git rev-parse HEAD`\n$shasum"
