Prefer GSS.framework on macOS over libgssapi_krb5.tbd when using vcpkg

On macOS, vcpkg toolchain sets the value of CMAKE_FIND_FRAMEWORK and
CMAKE_FIND_APPBUNDLE to LAST which causes an issue when it comes to
GSSAPI. This change in behavior leads to FindGSSAPI.cmake finding
`usr/lib/libgssapi_krb5.tbd → Kerberos.framework` instead, which is not
exactly what we want, and it misses some necessary symbols, and as a
result Network fails to build.¹

We need to make sure that we find `GSS.framework`. Here by dropping the
alternative name on Apple platform, we end up getting the Framework
even if vcpkg prefer finding the framework LAST.

[1]: https://github.com/microsoft/vcpkg/issues/23782

Pick-to: 6.5
Change-Id: I0e7e6272dcb0fdf2c746149d2969468d66ca9ec2
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

cmake/FindGSSAPI.cmake

@@ -12,12 +12,24 @@ find_path(GSSAPI_INCLUDE_DIRS
           HINTS ${PC_GSSAPI_INCLUDEDIR}
 )
 
+# On macOS, vcpkg opts for finding frameworks LAST. This is generally fine;
+# however, in the case of GSSAPI, `usr/lib/libgssapi_krb5.tbd` which is a
+# symlink to `Kerberos.framework` misses a few symols, e.g.,
+# `___gss_c_nt_hostbased_service_oid_desc`, and it causes build failure.
+# So, we need to make sure that we find `GSS.framework`.
+set(gssapi_library_names
+  GSS    # framework
+  gss    # solaris
+  gssapi # FreeBSD
+  gssapi_krb5
+)
+if(VCPKG_TARGET_TRIPLET AND APPLE)
+  list(REMOVE_ITEM gssapi_library_names "gssapi_krb5")
+endif()
+
 find_library(GSSAPI_LIBRARIES
              NAMES
-             GSS # framework
-             gss # solaris
-             gssapi # FreeBSD
-             gssapi_krb5
+             ${gssapi_library_names}
              HINTS ${PC_GSSAPI_LIBDIR}
 )
 
@@ -44,4 +56,3 @@ mark_as_advanced(GSSAPI_INCLUDE_DIRS GSSAPI_LIBRARIES)
 include(FeatureSummary)
 set_package_properties(GSSAPI PROPERTIES
   DESCRIPTION "Generic Security Services Application Program Interface")
-