[libxml2] configure: remove unused checks for libraries

[Nick Wellnhofer <nwellnhof src gnome org>]

commit 1a013ba711dd1a3825f4e2d4c0022d43c7bd860f
Author: Ben Boeckel <ben boeckel kitware com>
Date:   Mon Jul 26 20:11:56 2021 -0400

    configure: remove unused checks for libraries
    
    These libraries are queried for, but no code cares about the results, so
    remove the checks.

 CMakeLists.txt         | 2 --
 config.h.cmake.in      | 3 ---
 configure.ac           | 1 -
 macos/src/config-mac.h | 2 --
 os400/os400config.h.in | 6 ------
 vms/config.vms         | 1 -
 6 files changed, 15 deletions(-)
---
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 369a5c2f..41b69aeb 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -177,9 +177,7 @@ else()
        check_function_exists(isinf HAVE_ISINF)
        check_function_exists(isnan HAVE_ISNAN)
        check_library_exists(history append_history "" HAVE_LIBHISTORY)
-       check_library_exists(pthread pthread_join "" HAVE_LIBPTHREAD)
        check_library_exists(readline readline "" HAVE_LIBREADLINE)
-       check_library_exists(z gzread "" HAVE_LIBZ)
        check_include_files(limits.h HAVE_LIMITS_H)
        check_function_exists(localtime HAVE_LOCALTIME)
        check_include_files(malloc.h HAVE_MALLOC_H)
diff --git a/config.h.cmake.in b/config.h.cmake.in
index a4e0a3d9..61a8da12 100644
--- a/config.h.cmake.in
+++ b/config.h.cmake.in
@@ -64,9 +64,6 @@
 /* Define if history library is there (-lhistory) */
 #cmakedefine HAVE_LIBHISTORY 1
 
-/* Define if pthread library is there (-lpthread) */
-#cmakedefine HAVE_LIBPTHREAD 1
-
 /* Define if readline library is there (-lreadline) */
 #cmakedefine HAVE_LIBREADLINE 1
 
diff --git a/configure.ac b/configure.ac
index a4fb0768..60bd2767 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1062,7 +1062,6 @@ else
             AC_CHECK_HEADER(pthread.h,
                 AC_CHECK_LIB(pthread, pthread_join,[
                 THREAD_LIBS="-lpthread"
-                AC_DEFINE([HAVE_LIBPTHREAD], [], [Define if pthread library is there (-lpthread)])
                 AC_DEFINE([HAVE_PTHREAD_H], [], [Define if <pthread.h> is there])
                 WITH_THREADS="1"]))
         fi
diff --git a/macos/src/config-mac.h b/macos/src/config-mac.h
index d9b19b46..cd49aba1 100644
--- a/macos/src/config-mac.h
+++ b/macos/src/config-mac.h
@@ -9,7 +9,6 @@
 #define PACKAGE
 #define VERSION
 
-#undef HAVE_LIBZ
 #undef HAVE_LIBM
 #undef HAVE_ISINF
 #undef HAVE_ISNAN
@@ -17,7 +16,6 @@
 #undef HAVE_LIBREADLINE
 
 #define XML_SOCKLEN_T socklen_t
-#define HAVE_LIBPTHREAD
 #define HAVE_PTHREAD_H
 #define LIBXML_THREAD_ENABLED
 
diff --git a/os400/os400config.h.in b/os400/os400config.h.in
index 8e429878..322519f3 100644
--- a/os400/os400config.h.in
+++ b/os400/os400config.h.in
@@ -63,15 +63,9 @@
 /* Define if history library is there (-lhistory) */
 #undef HAVE_LIBHISTORY
 
-/* Define if pthread library is there (-lpthread) */
-#undef HAVE_LIBPTHREAD
-
 /* Define if readline library is there (-lreadline) */
 #undef HAVE_LIBREADLINE
 
-/* Have compression library */
-#undef HAVE_LIBZ
-
 /* Define to 1 if you have the <limits.h> header file. */
 #define HAVE_LIMITS_H           1
 
diff --git a/vms/config.vms b/vms/config.vms
index e9604302..430c6d23 100755
--- a/vms/config.vms
+++ b/vms/config.vms
@@ -10,7 +10,6 @@
 
 #undef PACKAGE
 #undef VERSION
-#undef HAVE_LIBZ
 #undef HAVE_LIBM
 #undef HAVE_ISINF
 #if defined(_IEEE_FP) && (__CRTL_VER >= 60200000)