Trac #18344: fix some case issues in sage-fix-pkg-checksums

The Sage developer's guide insists that the directories in `build/pkgs`
should be all lowercase. At the same time, we have started allowing
tarballs in `upstream` which have mixed case (e.g., Pillow and Sphinx).
The script `sage-fix-pkg-checksums` should allow for this, converting
the tarball name to lowercase before looking for the corresponding
directory.

URL: http://trac.sagemath.org/18344
Reported by: jhpalmieri
Ticket author(s): John Palmieri
Reviewer(s): Leif Leonhardy

src/bin/sage-fix-pkg-checksums

@@ -12,12 +12,17 @@ for upstream in "$@"
 do
     tarball=`basename "$upstream"`
     pkg_name=${tarball%%-*}
+    # Convert to lowercase for the directory name:
+    pkg_name_lc=`echo $pkg_name | tr '[:upper:]' '[:lower:]'`
     pkg_compression=${tarball#*.tar}   # gz or bz2
-    if [ -d "$SAGE_ROOT/build/pkgs/$pkg_name" ]; then
-        sage_version=`cat "$SAGE_ROOT/build/pkgs/$pkg_name/package-version.txt" | sed 's/\.p[0-9][0-9]*$//'`
+    if [ -d "$SAGE_ROOT/build/pkgs/$pkg_name_lc" ]; then
+        sage_version=`cat "$SAGE_ROOT/build/pkgs/$pkg_name_lc/package-version.txt" | sed 's/\.p[0-9][0-9]*$//'`
         if [ ${tarball%.tar*} = "$pkg_name-$sage_version" ]; then
             echo >&2 $tarball
-            checksums="$SAGE_ROOT/build/pkgs/$pkg_name/checksums.ini"
+            if [ "$pkg_name" != "$pkg_name_lc" ]; then
+                echo >&2 " ** Note: case mismatch between upstream/$tarball and build/pkgs/$pkg_name_lc. **"
+            fi
+            checksums="$SAGE_ROOT/build/pkgs/$pkg_name_lc/checksums.ini"
             echo "tarball=$pkg_name-VERSION.tar$pkg_compression" > $checksums
 
             echo -n "sha1=" >> $checksums