build/bin/sage-spkg-info: Fix and improve RST markup

build/bin/sage-spkg-info

@@ -7,8 +7,17 @@
 PKG_BASE=$1
 if [ -n "$OUTPUT_DIR" ]; then
     exec > "$OUTPUT_DIR"/$PKG_BASE.rst
+fi
+if [ -n "$OUTPUT_RST" ]; then
     echo ".. _spkg_$PKG_BASE:"
     echo
+    ref ()   { echo ":ref:\`$1\`"; }
+    issue () { echo ":issue:\`$1\`"; }
+    code ()  { echo "\`\`$*\`\`"; }
+else
+    ref ()   { echo "$1"; }
+    issue () { echo "https://github.com/sagemath/sage/issues/$1"; }
+    code ()  { echo "$1"; }
 fi
 PKG_SCRIPTS="$SAGE_ROOT/build/pkgs/$PKG_BASE"
 for ext in rst txt; do
@@ -45,9 +54,9 @@ for dep_file in dependencies dependencies_order_only; do
                 # Dependencies like $(BLAS)
                 \$\(*)      echo "- $dep";;
                 # Looks like a package
-                *)          if [ -n "$OUTPUT_RST" -a -r "$SAGE_ROOT/build/pkgs/$dep/SPKG.rst" ]; then
+                *)          if [ -r "$SAGE_ROOT/build/pkgs/$dep/SPKG.rst" ]; then
                                 # This RST label is set in src/doc/bootstrap
-                                echo "- :ref:\`spkg_$dep\`"
+                                echo "- $(ref spkg_$dep)"
                             else
                                 echo "- $dep"
                             fi;;
@@ -120,15 +129,15 @@ else
     if [ -f "${SPKG_CONFIGURE}" ]; then
         if grep -q SAGE_PYTHON_PACKAGE_CHECK "${SPKG_CONFIGURE}"; then
             echo "If the system package is installed and if the (experimental) option"
-            echo "--enable-system-site-packages is passed to ./configure, then ./configure"
+            echo "$(code --enable-system-site-packages) is passed to $(code ./configure), then $(code ./configure)"
             echo "will check if the system package can be used."
         else
-            echo "If the system package is installed, ./configure will check if it can be used."
+            echo "If the system package is installed, $(code ./configure) will check if it can be used."
         fi
     else
         echo "However, these system packages will not be used for building Sage"
-        echo "because spkg-configure.m4 has not been written for this package;"
-        echo "see https://github.com/sagemath/sage/issues/27330"
+        echo "because $(code spkg-configure.m4) has not been written for this package;"
+        echo "see $(issue 27330)"
     fi
 fi
 echo