Trac #29373: Upgrade freetype to 2.10.1 to fix installation on slackw…

…are-14.2

freetype fails to install on `slackware-14.2-minimal`, as can be seen at
https://github.com/mkoeppe/sage/runs/520449598 (via #29354):

{{{
./builds/unix/libtool --tag=RC --mode=compile windres -o
/sage/local/var/tmp/sage/build/freetype-2.9.1/src/objs/ftver.lo
/sage/local/var/tmp/sage/build/freetype-2.9.1/src/src/base/ftver.rc
libtool: compile:  windres
/sage/local/var/tmp/sage/build/freetype-2.9.1/src/src/base/ftver.rc  -o
/sage/local/var/tmp/sage/build/freetype-2.9.1/src/objs/.libs/ftver.o
/sage/local/var/tmp/sage/build/freetype-2.9.1/src/src/base/ftver.rc:19:2
0: fatal error: windows.h: No such file or directory
compilation terminated.
windres: preprocessing failed.
}}}

The upgrade to 2.10.1 fixes it. The upstream tarball URL is in
checksums.ini. To test the update on this branch: Use `make SAGE_SPKG
="sage-spkg -o" freetype`; this will download the new upstream package
automatically.

URL: https://trac.sagemath.org/29373
Reported by: mkoeppe
Ticket author(s): Matthias Koeppe
Reviewer(s): Jonathan Kliem

build/pkgs/freetype/checksums.ini

@@ -1,4 +1,5 @@
 tarball=freetype-VERSION.tar.bz2
-sha1=220c82062171c513e4017c523d196933c9de4a7d
-md5=60ef7d8160cd4bf8cb118ee9d65367ca
-cksum=1149809609
+sha1=3296b64ad1e7540289f22e4b6383e26e928b0a20
+md5=c50a3c9e5e62bdc938a6e1598a782947
+cksum=2822306030
+upstream_url=https://download.savannah.gnu.org/releases/freetype/freetype-VERSION.tar.gz

build/pkgs/freetype/package-version.txt

@@ -1 +1 @@
-2.9.1
+2.10.1