CMake: fix MIT/Heimdal Kerberos detection

- fix syntax error in FindGSS.cmake
- correct krb5 include directory. FindGSS exports
  "GSS_INCLUDE_DIR" variable.

Closes https://github.com/curl/curl/pull/3316

CMake/FindGSS.cmake

@@ -68,7 +68,7 @@ if(NOT _GSS_FOUND) #not found by pkg-config. Let's take more traditional approac
       # should also work in an odd case when multiple directories are given
       string(STRIP "${_GSS_CFLAGS}" _GSS_CFLAGS)
       string(REGEX REPLACE " +-I" ";" _GSS_CFLAGS "${_GSS_CFLAGS}")
-      string(REGEX REPLACE " +-([^I][^ \\t;]*)" ";-\\1"_GSS_CFLAGS "${_GSS_CFLAGS}")
+      string(REGEX REPLACE " +-([^I][^ \\t;]*)" ";-\\1" _GSS_CFLAGS "${_GSS_CFLAGS}")
 
       foreach(_flag ${_GSS_CFLAGS})
         if(_flag MATCHES "^-I.*")
@@ -91,7 +91,7 @@ if(NOT _GSS_FOUND) #not found by pkg-config. Let's take more traditional approac
       # this script gives us libraries and link directories. Blah. We have to deal with it.
       string(STRIP "${_GSS_LIB_FLAGS}" _GSS_LIB_FLAGS)
       string(REGEX REPLACE " +-(L|l)" ";-\\1" _GSS_LIB_FLAGS "${_GSS_LIB_FLAGS}")
-      string(REGEX REPLACE " +-([^Ll][^ \\t;]*)" ";-\\1"_GSS_LIB_FLAGS "${_GSS_LIB_FLAGS}")
+      string(REGEX REPLACE " +-([^Ll][^ \\t;]*)" ";-\\1" _GSS_LIB_FLAGS "${_GSS_LIB_FLAGS}")
 
       foreach(_flag ${_GSS_LIB_FLAGS})
         if(_flag MATCHES "^-l.*")

CMakeLists.txt

@@ -585,7 +585,7 @@ if(CMAKE_USE_GSSAPI)
 
     message(STATUS "Found ${GSS_FLAVOUR} GSSAPI version: \"${GSS_VERSION}\"")
 
-    list(APPEND CMAKE_REQUIRED_INCLUDES ${GSS_INCLUDE_DIRECTORIES})
+    list(APPEND CMAKE_REQUIRED_INCLUDES ${GSS_INCLUDE_DIR})
     check_include_file_concat("gssapi/gssapi.h"  HAVE_GSSAPI_GSSAPI_H)
     check_include_file_concat("gssapi/gssapi_generic.h" HAVE_GSSAPI_GSSAPI_GENERIC_H)
     check_include_file_concat("gssapi/gssapi_krb5.h" HAVE_GSSAPI_GSSAPI_KRB5_H)
@@ -621,7 +621,7 @@ if(CMAKE_USE_GSSAPI)
 
     endif()
 
-    include_directories(${GSS_INCLUDE_DIRECTORIES})
+    include_directories(${GSS_INCLUDE_DIR})
     link_directories(${GSS_LINK_DIRECTORIES})
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${GSS_COMPILER_FLAGS}")
     set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${GSS_LINKER_FLAGS}")