Trac #28231: spkg-configure.m4 for lrcalc

lrcalc is available in Debian (`lrcalc` and `liblrcalc-dev`) and in
Fedora (`lrcalc-devel`)

On Fedora one also needs to run "module load lrcalc-x86_64" to add the
location of `rlcalc` binaries to PATH, although it appears to be not
important, as only the dylib of lrcalc is used in Sage.

URL: https://trac.sagemath.org/28231
Reported by: dimpase
Ticket author(s): Dima Pasechnik
Reviewer(s): Isuru Fernando

build/pkgs/lrcalc/spkg-configure.m4

@@ -0,0 +1,9 @@
+SAGE_SPKG_CONFIGURE([lrcalc], [
+    AC_CHECK_HEADERS([lrcalc/schublib.h], [
+          AC_SEARCH_LIBS([mult_poly_schubert], [lrcalc], [], [sage_spkg_install_lrcalc=yes])
+    ], [sage_spkg_install_lrcalc=yes],
+    [[#ifndef _HASHTAB_H
+      #include <lrcalc/hashtab.h>
+      #include <lrcalc/vector.h>
+      #endif]])
+])