Trac #31584: Fix suitesparse/cvxopt /usr/local leakage

We fix a simple bug in our build system:

The value of `SAGE_SUITESPARSE_LOCALINSTALL` is set in
`build/pkgs/suitesparse/spkg-configure.m4` but is not actually passed on
to `build/pkgs/cvxopt/spkg-install.in`.  A different variable,
`SAGE_SUITESPARSE_PREFIX`, is passed by `build/bin/sage-build-env-
config.in` from the configure stage to the build stage, but it is never
set or used.
{{{
$ git grep SAGE_SUITESPARSE
build/bin/sage-build-env-config.in:export
SAGE_SUITESPARSE_PREFIX="@SAGE_SUITESPARSE_PREFIX@"
build/pkgs/cvxopt/spkg-install.in:if test
"x$SAGE_SUITESPARSE_LOCALINSTALL" != "x"; then
build/pkgs/suitesparse/spkg-configure.m4:
AC_SUBST(SAGE_SUITESPARSE_LOCALINSTALL, ['$SAGE_LOCAL'])
build/pkgs/suitesparse/spkg-configure.m4:
AC_SUBST(SAGE_SUITESPARSE_LOCALINSTALL, [''])
}}}

As a result, `suitesparse` from `/usr/local` can leak in, as observed in
https://trac.sagemath.org/ticket/31567?replyto=25#comment:25

Clearly these two variables were intended to be the same variable. We
fix this.  This unified variable, `SAGE_SUITESPARSE_PREFIX`, is
analogous to other variables `SAGE_..._PREFIX`.

URL: https://trac.sagemath.org/31584
Reported by: mkoeppe
Ticket author(s): Matthias Koeppe
Reviewer(s): Michael Orlitzky

Author: Release Manager

build/pkgs/configure/checksums.ini

@@ -1,4 +1,4 @@
 tarball=configure-VERSION.tar.gz
-sha1=a38ba439948866832495e453b2febed61a232256
-md5=72ad56533ec90f5bcec51d4005387f15
-cksum=2631020116
+sha1=e50050ec2ee230ad38ac794636ada8c96f62f586
+md5=d3778f173c5d6dd83f69826398c8410d
+cksum=4238671374

build/pkgs/configure/package-version.txt

@@ -1 +1 @@
-1a6e82a160b277ae72ecfd7406060a28ab9c3eb4
+c2359582ba43e8c9b6883f6d52d70f16ffb9fac5

build/pkgs/cvxopt/spkg-install.in

@@ -65,9 +65,9 @@ export CVXOPT_BLAS_LIB="$(cvxopt_output l blas)"
 export CVXOPT_BLAS_LIB_DIR="$(pkg-config --variable=libdir blas)"
 export CVXOPT_LAPACK_LIB="$(cvxopt_output l lapack)"
 
-if test "x$SAGE_SUITESPARSE_LOCALINSTALL" != "x"; then
-   export CVXOPT_SUITESPARSE_LIB_DIR="${SAGE_LOCAL}"
-   export CVXOPT_SUITESPARSE_INC_DIR="${SAGE_LOCAL}/include"
+if test "x$SAGE_SUITESPARSE_PREFIX" != "x"; then
+   export CVXOPT_SUITESPARSE_LIB_DIR="${SAGE_SUITESPARSE_PREFIX}"
+   export CVXOPT_SUITESPARSE_INC_DIR="${SAGE_SUITESPARSE_PREFIX}/include"
 fi
 
 export CVXOPT_BUILD_GLPK=1

build/pkgs/suitesparse/spkg-configure.m4

@@ -17,8 +17,8 @@ SAGE_SPKG_CONFIGURE([suitesparse], [
       sage_spkg_install_suitesparse=yes])
 ], [], [], [
     AS_IF([test x$sage_spkg_install_suitesparse = xyes], [
-       AC_SUBST(SAGE_SUITESPARSE_LOCALINSTALL, ['$SAGE_LOCAL'])
+       AC_SUBST(SAGE_SUITESPARSE_PREFIX, ['$SAGE_LOCAL'])
     ], [
-       AC_SUBST(SAGE_SUITESPARSE_LOCALINSTALL, [''])
+       AC_SUBST(SAGE_SUITESPARSE_PREFIX, [''])
     ])
 ])