libcurl.pc: add more Requires.private/Requires dependencies

- add `libmsh3` reference from cmake and autotools.

- add `mit-krb5-gssapi` reference from cmake.

It leaves GSS not set from autotools. The handling of heimdal in cmake
is fuzzy, that's probably missing too.

Follow-up to f057de5a1a #13911
Closes #14072

CMakeLists.txt

@@ -765,6 +765,7 @@ if(USE_MSH3)
   set(USE_MSH3 ON)
   include_directories(${MSH3_INCLUDE_DIRS})
   list(APPEND CURL_LIBS ${MSH3_LIBRARIES})
+  list(APPEND LIBCURL_PC_REQUIRES_PRIVATE "libmsh3")
 endif()
 
 option(USE_OPENSSL_QUIC "Use openssl and nghttp3 libraries for HTTP/3 support" OFF)
@@ -1048,6 +1049,9 @@ if(CURL_USE_GSSAPI)
     set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${GSS_LINKER_FLAGS}")
     set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${GSS_LINKER_FLAGS}")
     list(APPEND CURL_LIBS ${GSS_LIBRARIES})
+    if(GSS_FLAVOUR STREQUAL "MIT")
+      list(APPEND LIBCURL_PC_REQUIRES_PRIVATE "mit-krb5-gssapi")
+    endif()
   else()
     message(WARNING "GSSAPI support has been requested but no supporting libraries found. Skipping.")
   endif()

configure.ac

@@ -3491,7 +3491,8 @@ if test X"$want_msh3" != Xno; then
         AC_SUBST(USE_MSH3, [1])
         CURL_LIBRARY_PATH="$CURL_LIBRARY_PATH:$DIR_MSH3"
         export CURL_LIBRARY_PATH
-        AC_MSG_NOTICE([Added $DIR_MSH3 to CURL_LIBRARY_PATH]),
+        AC_MSG_NOTICE([Added $DIR_MSH3 to CURL_LIBRARY_PATH])
+        LIBCURL_PC_REQUIRES_PRIVATE="$LIBCURL_PC_REQUIRES_PRIVATE libmsh3"
         experimental="$experimental HTTP3"
      )
     ],