gh-35895: gap: make libgap APIs for function calls available

    
... and use them in two places. The rest will be dealt with in a future
PR.
    
URL: #35895
Reported by: Max Horn
Reviewer(s): Marc Mezzarobba

src/sage/libs/gap/element.pyx

@@ -118,13 +118,13 @@ cdef char *capture_stdout(Obj func, Obj obj):
         GAP_Enter()
         s = NEW_STRING(0)
         output_text_string = GAP_ValueGlobalVariable("OutputTextString")
-        stream = CALL_2ARGS(output_text_string, s, GAP_True)
+        stream = GAP_CallFunc2Args(output_text_string, s, GAP_True)
 
         l = GAP_NewPlist(1)
         GAP_AssList(l, 1, obj)
 
         CALL_WITH_STREAM = GAP_ValueGlobalVariable("CALL_WITH_STREAM")
-        CALL_3ARGS(CALL_WITH_STREAM, stream, func, l)
+        GAP_CallFunc3Args(CALL_WITH_STREAM, stream, func, l)
         return GAP_CSTR_STRING(s)
     finally:
         GAP_Leave()

src/sage/libs/gap/gap_includes.pxd

@@ -68,6 +68,13 @@ cdef extern from "gap/libgap-api.h" nogil:
     cdef Obj GAP_True
     cdef Obj GAP_False
 
+    Obj GAP_CallFuncList(Obj func, Obj args);
+    Obj GAP_CallFuncArray(Obj func, UInt narg, Obj * args);
+    Obj GAP_CallFunc0Args(Obj func);
+    Obj GAP_CallFunc1Args(Obj func, Obj a1);
+    Obj GAP_CallFunc2Args(Obj func, Obj a1, Obj a2);
+    Obj GAP_CallFunc3Args(Obj func, Obj a1, Obj a2, Obj a3);
+
     bint GAP_IsMacFloat(Obj obj)
     double GAP_ValueMacFloat(Obj obj)