sagemathgh-38715: Define feature sage.libs.giac

<!-- ^ Please provide a concise and informative title. -->
<!-- ^ Don't put issue numbers in the title, do this in the PR
description below. -->
<!-- ^ For example, instead of "Fixes sagemath#12345" use "Introduce new method
to calculate 1 + 2". -->
<!-- v Describe your changes below in detail. -->
<!-- v Why is this change required? What problem does it solve? -->
<!-- v If this PR resolves an open issue, please link to it here. For
example, "Fixes sagemath#12345". -->

The tag `# needs sage.libs.giac` has already appeared in a few places,
but the feature was not defined.

- This complements sagemath#38672 @orlitzky
- Cherry-picked from from sagemath#35095

### 📝 Checklist

<!-- Put an `x` in all the boxes that apply. -->

- [x] The title is concise and informative.
- [x] The description explains in detail what this PR is about.
- [x] I have linked a relevant issue or discussion.
- [ ] I have created tests covering the changes.
- [ ] I have updated the documentation and checked the documentation
preview.

### ⌛ Dependencies

<!-- List all open PRs that this PR logically depends on. For example,
-->
<!-- - sagemath#12345: short description why this is a dependency -->
<!-- - sagemath#34567: ... -->

URL: sagemath#38715
Reported by: Matthias Köppe
Reviewer(s): Kwankyu Lee

build/pkgs/configure/checksums.ini

@@ -1,3 +1,3 @@
 tarball=configure-VERSION.tar.gz
-sha1=2cdffd348b8a4de62b51e1f6c37a7d414004c09e
-sha256=273c37842eedefc3575e34bb14819ab3738a32c39ae634f2342bb50baa740c60
+sha1=5b7e639cb106cf623a88ce1ba0d81aa08be21f9d
+sha256=9c4a37481d868fb2a8048da802f2f686e7f6dc0222186af68c0b943c4a21d1de

build/pkgs/configure/package-version.txt

@@ -1 +1 @@
-9b58ceaa68960b38142f27fdfc04373301da4e46
+c209e729573ed526c7c10b39a7df3f4284420f84

src/sage/features/sagemath.py

@@ -537,6 +537,32 @@ def __init__(self):
                              spkg='sagemath_ntl', type='standard')
 
 
+class sage__libs__giac(JoinFeature):
+    r"""
+    A :class:`sage.features.Feature` describing the presence of :mod:`sage.libs.giac`.
+
+    In addition to the modularization purposes that this tag serves,
+    it also provides attribution to the upstream project.
+
+    TESTS::
+
+        sage: from sage.features.sagemath import sage__libs__giac
+        sage: sage__libs__giac().is_present()                                           # needs sage.libs.giac
+        FeatureTestResult('sage.libs.giac', True)
+    """
+    def __init__(self):
+        r"""
+        TESTS::
+
+            sage: from sage.features.sagemath import sage__libs__giac
+            sage: isinstance(sage__libs__giac(), sage__libs__giac)
+            True
+        """
+        JoinFeature.__init__(self, 'sage.libs.giac',
+                             [PythonModule('sage.libs.giac.giac')],
+                             spkg='sagemath_giac', type='standard')
+
+
 class sage__libs__homfly(JoinFeature):
     r"""
     A :class:`sage.features.Feature` describing the presence of :mod:`sage.libs.homfly`.
@@ -1155,6 +1181,7 @@ def all_features():
             sage__libs__ecl(),
             sage__libs__flint(),
             sage__libs__gap(),
+            sage__libs__giac(),
             sage__libs__homfly(),
             sage__libs__linbox(),
             sage__libs__m4ri(),