Trac #20710: upgrade glpk to 4.60

I suggest to upgrade `glpk` to the latest available version (4.60 at the
time of writing). The current version has been superseded in Gentoo and
the formatting of the output has changed.
Here are the tasks for this upgrade:

1. use `spkg-src` instead of patching `configure` directly

2. some part of `have_error.patch` is now upstream, but not every piece
of that patch was accepted

3. clean up `SPKG.txt` and other files so they are reflecting the
current reality more closely without obsolete historical comments

'''Tarball''': http://www.lmona.de/files/sage/glpk-4.60.tar.bz2
(generated with `spkg-src`)

URL: https://trac.sagemath.org/20710
Reported by: fbissey
Ticket author(s): François Bissey
Reviewer(s): Matthias Koeppe, Jeroen Demeyer

build/pkgs/glpk/SPKG.txt

@@ -38,13 +38,7 @@ http://www.gnu.org/software/glpk/#maintainer
 
 == Special Update/Build Instructions == 
 
- * It should be sufficient to pass `--with-<package>="$SAGE_LOCAL"` 
-   (where <package>={gmp,zlib}) instead of adding Sage's directories 
-   to `CPPFLAGS` and `LDFLAGS`; see comment in `spkg-install`. 
-   Turns out that (as of version 4.55) 
-   1) GLPK unconditionally uses its own copy of zlib (see above), 
-      and the `configure` option `--with-zlib` is no longer valid; 
-   2) `configure` doesn't support specifying the location of the GMP 
+ * `configure` doesn't support specifying the location of the GMP 
       library to use; only `--with-gmp[=yes]` or `--with-gmp=no` 
       are valid options.  (So we *have to* add Sage's include and 
       library directories to `CPPFLAGS` and `LDFLAGS`, respectively.) 
@@ -56,8 +50,10 @@ http://www.gnu.org/software/glpk/#maintainer
 
 === Patches ===
 
- * cygwin_sharedlib.patch: Let a shared library be built on Cygwin by
+ * All patches below are currently used by spkg-src
+   * src/01-zlib.patch: don't build the included zlib library.
+   * src/02-cygwin_sharedlib.patch: Let a shared library be built on Cygwin by
    passing the -no-undefined flag to libtool.
- * zlib.patch: don't build the included zlib library.
- * build_system/: contains patches prior to re-autotoolification.
 
+   The numbering reflect the order in which they have been created from
+   glpk pristine's sources

build/pkgs/glpk/checksums.ini

@@ -1,4 +1,4 @@
-tarball=glpk-VERSION.tar.gz
-sha1=893058aada022a8dfc63c675ebcd7e7e86a3a363
-md5=c632a7a631b8aed02e28eafcd99477f7
-cksum=2152970452
+tarball=glpk-VERSION.tar.bz2
+sha1=385c6a53253d1732851abb62b2db0f9739f24b2e
+md5=6295b29f17fc74f4210a942b68993416
+cksum=1143525289

build/pkgs/glpk/package-version.txt

@@ -1 +1 @@
-4.55.p1
+4.60.p0